<%@ page import="java.util.Date" %>
<%@ page import="java.text.SimpleDateFormat" %>
<%@ page import="java.net.URLEncoder" %>
<%@ page import="java.net.URLDecoder" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>itcast</title>
</head>
<body>

<%

    //1.获取所有Cookie
    Cookie[] cookies = request.getCookies();
    boolean flag = false;//没有cookie为lastTime
    //2.遍历cookie数组
    if(cookies != null && cookies.length > 0){
        for (Cookie cookie : cookies) {
            //3.获取cookie的名称
            String name = cookie.getName();
            //4.判断名称是否是：lastTime
            if("lastTime".equals(name)){
                //有该Cookie，不是第一次访问

                flag = true;//有lastTime的cookie

                //设置Cookie的value
                //获取当前时间的字符串，重新设置Cookie的值，重新发送cookie
                Date date  = new Date();
                SimpleDateFormat sdf = new SimpleDateFormat("yyyy年MM月dd日 HH:mm:ss");
                String str_date = sdf.format(date);
                System.out.println("编码前："+str_date);
                //URL编码
                str_date = URLEncoder.encode(str_date,"utf-8");
                System.out.println("编码后："+str_date);
                cookie.setValue(str_date);
                //设置cookie的存活时间
                cookie.setMaxAge(60 * 60 * 24 * 30);//一个月
                response.addCookie(cookie);


                //响应数据
                //获取Cookie的value，时间
                String value = cookie.getValue();
                System.out.println("解码前："+value);
                //URL解码：
                value = URLDecoder.decode(value,"utf-8");
                System.out.println("解码后："+value);
                %>
            <h1>欢迎回来，您上次访问时间为:<%=value%></h1>
            <input>

<%



                break;

            }
        }
    }


    if(cookies == null || cookies.length == 0 || flag == false){
        //没有，第一次访问

        //设置Cookie的value
        //获取当前时间的字符串，重新设置Cookie的值，重新发送cookie
        Date date  = new Date();
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy年MM月dd日 HH:mm:ss");
        String str_date = sdf.format(date);
        System.out.println("编码前："+str_date);
        //URL编码
        str_date = URLEncoder.encode(str_date,"utf-8");
        System.out.println("编码后："+str_date);

        Cookie cookie = new Cookie("lastTime",str_date);
        //设置cookie的存活时间
        cookie.setMaxAge(60 * 60 * 24 * 30);//一个月
        response.addCookie(cookie);

%>

        <h1>您好，欢迎您首次访问</h1>
<span></span>

<%
    }

%>

<input>




</body>
</html>

8.6 指令

作用：用于配置JSP页面，导入资源文件

格式：

<%@ 指令名称 属性名1=属性值1 属性名2=属性值2 ... %>

分类：
1. page：配置JSP页面的
  - contentType：等同于response.setContentType()
    1. 设置响应体的mime类型以及字符集
    2. 设置当前jsp页面的编码（只能是高级的IDE才能生效，如果使用低级工具，则需要设置pageEncoding属性设置当前页面的字符集）
  - import：导包
  - errorPage：当前页面发生异常后，会自动跳转到指定的错误页面
  - isErrorPage：标识当前也是是否是错误页面。
    - true：是，可以使用内置对象exception
    - false：否。默认值。不可以使用内置对象exception
2. include ：页面包含的。导入页面的资源文件
```
<%@include file="top.jsp"%>
```

taglib ：导入资源

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

prefix：前缀，自定义的

8.7 注释:

html注释： :只能注释html代码片段
jsp注释：推荐使用
<%-- --%>：可以注释所有

8.8 内置对象

在jsp页面中不需要创建，直接使用的对象

变量名	真实类型	作用
pageContext	PageContext	当前页面共享数据，还可以获取其他八个内置对象
request	HttpServletRequest	一次请求访问的多个资源(转发)
session	HttpSession	一次会话的多个请求间
application	ServletContext	所有用户间共享数据
response	HttpServletResponse	响应对象
page	Object	当前页面(Servlet)的对象 this
out	JspWriter	输出对象，数据输出到页面上
config	ServletConfig	Servlet的配置对象
exception	Throwable	异常对象

8.9 MVC：开发模式

8.9.1 jsp演变历史

早期只有servlet，只能使用response输出标签数据，非常麻烦
后来又jsp，简化了Servlet的开发，如果过度使用jsp，在jsp中即写大量的java代码，有写html表，造成难于维护，难于分工协作
再后来，java的web开发，借鉴mvc开发模式，使得程序的设计更加合理性

8.9.2 MVC：

M：Model，模型。JavaBean
- 完成具体的业务操作，如：查询数据库，封装对象
V：View，视图。JSP
- 展示数据
C：Controller，控制器。Servlet
- 获取用户的输入
- 调用模型
- 将数据交给视图进行展示

8.9.3 MVC优缺点：

优点：

耦合性低，方便维护，可以利于分工协作
重用性高

缺点：

使得项目架构变得复杂，对开发人员要求高

8.10 EL表达式

8.10.1 概述

概念：Expression Language 表达式语言
作用：替换和简化jsp页面中java代码的编写
语法：${表达式}
注意：
- jsp默认支持el表达式的。如果要忽略el表达式
  1. 设置jsp中page指令中：isELIgnored=“true” 忽略当前jsp页面中所有的el表达式
  2. \ ${表达式} ：忽略当前这个el表达式

8.10.2 使用

运算：

运算符：
1. 算数运算符： + - * /(div) %(mod)
2. 比较运算符： > < >= <= == !=
3. 逻辑运算符： &&(and) ||(or) !(not)
4. 空运算符： empty
  - 功能：用于判断字符串、集合、数组对象是否为null或者长度是否为0
  - ${empty list}:判断字符串、集合、数组对象是否为null或者长度为0
  - ${not empty str}:表示判断字符串、集合、数组对象是否不为null 并且长度>0

获取值

el表达式只能从域对象中获取值
语法：

${域名称.键名}：从指定域中获取指定键的值
- 域名称：
  - pageScope --> pageContext
  - requestScope --> request
  - sessionScope --> session
  - applicationScope --> application（ServletContext）
- 举例：在request域中存储了name=张三
- 获取：${requestScope.name}
${键名}：表示依次从最小的域中查找是否有该键对应的值，直到找到为止。

获取对象、List集合、Map集合的值

对象：${域名称.键名.属性名}

本质上会去调用对象的getter方法

 <%
        User user=new User("张三",34,new Date());
        request.setAttribute("u",user);
    %>

    <h1>el获取对象的值</h1>
    ${requestScope.u}<br>
    ${requestScope.u.name}<br>
    ${u.age}<br>
    ${u.birthday}<br>

List集合：${域名称.键名[索引]}

Map集合：

${域名称.键名.key名称}
${域名称.键名["key名称"]}

隐式对象：

el表达式中有11个隐式对象

pageContext：

获取jsp其他八个内置对象

${pageContext.request.contextPath}：动态获取虚拟目录

8.11 JSTL

8.11.1 概述

概念：JavaServer Pages Tag Library

JSP标准标签库

是由Apache组织提供的开源的免费的jsp标签

作用：用于简化和替换jsp页面上的java代码

8.11.2 使用步骤：

导入jstl相关jar包

引入标签库：taglib指令： <%@ taglib %>

使用标签

8.11.3 常用的JSTL标签

if:相当于java代码的if语句

属性：

test 必须属性，接受boolean表达式

如果表达式为true，则显示if标签体内容，如果为false，则不显示标签体内容

一般情况下，test属性值会结合el表达式一起使用

注意： c:if标签没有else情况，想要else情况，则可以在定义一个c:if标签

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%--
  Created by IntelliJ IDEA.
  User: Lenovo
  Date: 2021/7/24
  Time: 19:04
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>c:if</title>
</head>
<body>
    <c:if test="true">
        我是真。。。。
    </c:if>

    <%
        int a=6;
    %>

    <c:if test="${number % 2 == 0}">
        是偶数。。。。
    </c:if>
</body>
</html>

choose:相当于java代码的switch语句

相当于switch声明

使用when标签做判断，相当于case

使用otherwise标签做其他情况的声明，相当于default 、

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%--
  Created by IntelliJ IDEA.
  User: Lenovo
  Date: 2021/7/24
  Time: 19:12
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>c:choose</title>
</head>
<body>
    <%
        request.setAttribute("number",5);
    %>
    <c:choose>
        <c:when test="${number==1}">周一</c:when>
        <c:when test="${number==2}">周二</c:when>
        <c:when test="${number==3}">周三</c:when>
        <c:when test="${number==4}">周四</c:when>
        <c:when test="${number==5}">周五</c:when>
        <c:when test="${number==6}">周六</c:when>
        <c:when test="${number==7}">周七</c:when>
        <c:otherwise>您输入的有误!!!</c:otherwise>
    </c:choose>
</body>
</html>

foreach:相当于java代码的for语句

完成重复的操作
for(int i = 0; i < 10; i ++){

}

属性：

begin：开始值

end：结束值

var：临时变量

step：步长

varStatus：循环状态对象
遍历容器
List< User> list;
for(User user : list){

}

属性：
items:容器对象
var:容器中元素的临时变量
varStatus:循环状态对象
index:容器中元素的索引，从0开始
count:循环次数，从1开始

<%@ page import="java.util.ArrayList" %>
<%@ page import="java.util.List" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>

<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

<html>
<head>
    <title>foreach标签</title>
</head>
<body>


<c:forEach begin="1" end="10" var="i" step="2" varStatus="s">
    ${i} <h3>${s.index}<h3> <h4> ${s.count} </h4><br>

</c:forEach>

    <hr>


    <%
        List list = new ArrayList();
        list.add("aaa");
        list.add("bbb");
        list.add("ccc");

        request.setAttribute("list",list);


    %>

    <c:forEach items="${list}" var="str" varStatus="s">

            ${s.index} ${s.count} ${str}<br>

    </c:forEach>


</body>
</html>

练习

需求：在request域中有一个存有User对象的List集合。需要使用jstl+el将list集合数据展示到jsp页面的表格table中

package itcast.pojo;

import java.util.Date;

public class User {
    private  String name;
    private  int age;
    private Date birthday;

    public User(String name, int age, Date birthday) {
        this.name = name;
        this.age = age;
        this.birthday = birthday;
    }

    public User() {

    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    @Override
    public String toString() {
        return "User{" +
                "name='" + name + '\'' +
                ", age=" + age +
                ", birthday=" + birthday +
                '}';
    }
}

<%@ page import="cn.itcast.domain.User" %>
<%@ page import="java.util.List" %>
<%@ page import="java.util.ArrayList" %>
<%@ page import="java.util.Date" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

<html>
<head>
    <title>test</title>
</head>
<body>

<%

    List list = new ArrayList();
    list.add(new User("张三",23,new Date()));
    list.add(new User("李四",24,new Date()));
    list.add(new User("王五",25,new Date()));

    request.setAttribute("list",list);


%>

<table  width="500" align="center">
    <tr>
        <th>编号</th>
        <th>姓名</th>
        <th>年龄</th>
        <th>生日</th>
    </tr>
    <%--数据行--%>
    <c:forEach items="${list}" var="user" varStatus="s">

        <c:if test="${s.count % 2 != 0}">

            <tr bgcolor="red">
                <td>${s.count}</td>
                <td>${user.name}</td>
                <td>${user.age}</td>
                <td>${user.birStr}</td>
            </tr>
        </c:if>

        <c:if test="${s.count % 2 == 0}">

            <tr  bgcolor="green">
                <td>${s.count}</td>
                <td>${user.name}</td>
                <td>${user.age}</td>
                <td>${user.birStr}</td>
            </tr>
        // </c:if>
    </c:forEach>

</table>






</body>
</html>

8.12 三层架构：软件设计架构

界面层(表示层web)：用户看的得界面。用户可以通过界面上的组件和服务器进行交互

业务逻辑层service：处理业务逻辑的。

数据访问层dao：操作数据存储文件。

8.12.1案例：用户信息列表展示

需求：用户信息的增删改查操作
设计：
- 技术选型：Servlet+JSP+MySQL+JDBCTempleat+Duird+BeanUtilS+tomcat
- 数据库设计：
开发：

环境搭建
创建数据库环境
创建项目，导入需要的jar包
编码

测试
部署运维

1 环境搭建

创建数据库，添加数据

create database day17; -- 创建数据库		
use day17; 			   -- 使用数据库		
create table user(   -- 创建表			
	id int primary key auto_increment,			
	name varchar(20) not null,			
	gender varchar(5),			
	age int,			
	address varchar(32),			
	qq	varchar(20),			
	email varchar(50)		
);

INSERT INTO `user` VALUES (1, '张三', '男', 23, '河北省', '2623222222', '[email protected]');
INSERT INTO `user` VALUES (2, '李四', '男', 33, '河南省', '2625555555', '[email protected]');
INSERT INTO `user` VALUES (3, '王五', '女', 27, '重庆', '4522222268', '[email protected]');
INSERT INTO `user` VALUES (4, '柳六', '男', 13, '陕西', '12345', '[email protected]');
INSERT INTO `user` VALUES (5, '钱七', '女', 15, '北京', '88888', '[email protected]');

导入相关jar包

导入静态资源

导入druid.properties文件

driverClassName=com.mysql.jdbc.Driver
url=jdbc:mysql:///javawebs
username=root
password=root
# 初始化连接数量
initialSize=5
# 最大连接数
maxActive=10
# 最大等待时间
maxWait=3000

2 列表查询

User

package cn.gtt.pojo;

public class User {
    private int id;
    private  String name;
    private  String genter;
    private int age;
    private  String address;
    private  String qq;
    private String email;

    public User(int id, String name, String genter, int age, String address, String qq, String email) {
        this.id = id;
        this.name = name;
        this.genter = genter;
        this.age = age;
        this.address = address;
        this.qq = qq;
        this.email = email;
    }

    public User() {
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getGenter() {
        return genter;
    }

    public void setGenter(String genter) {
        this.genter = genter;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public String getQq() {
        return qq;
    }

    public void setQq(String qq) {
        this.qq = qq;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", genter='" + genter + '\'' +
                ", age=" + age +
                ", address='" + address + '\'' +
                ", qq='" + qq + '\'' +
                ", email='" + email + '\'' +
                '}';
    }
}

UserDao

package cn.gtt.dao;

import cn.gtt.pojo.User;

import java.util.List;

/**
 * 用户操作的dao
 */
public interface UserDao {
    /**
     * 查询所有用户信息
     */
    public List<User> findAll();
}

UserDaoImpl

package cn.gtt.dao.Impl;

import cn.gtt.dao.UserDao;
import cn.gtt.pojo.User;
import cn.gtt.util.JDBCUtils;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;

import java.util.List;

public class UserDaoImpl implements UserDao {

    private  JdbcTemplate jdbcTemplate=new JdbcTemplate(JDBCUtils.getDataSource());
    /**
     * 查询所有用户信息
     */
    @Override
    public List<User> findAll() {
//        使用JDBC操作数据库
        String sql="select * from user";
        List<User> users = jdbcTemplate.query(sql, new BeanPropertyRowMapper<User>(User.class));
        return users;
    }
}

UserService

package cn.gtt.service;

import cn.gtt.pojo.User;

import java.util.List;

/**
 * 用户管理的业务接口
 */
public interface UserService {
    /**
     * 查询所有用户信息
     * @return
     */
    public List<User> findAll();
}

UserServiceImpl

package cn.gtt.service.Impl;

import cn.gtt.dao.Impl.UserDaoImpl;
import cn.gtt.dao.UserDao;
import cn.gtt.pojo.User;
import cn.gtt.service.UserService;

import java.util.List;

public class UserServiceImpl implements UserService {

    UserDao userDao=new UserDaoImpl() ;
    /**
     * 查询所有用户信息
     */
    @Override
    public List<User> findAll() {
//        调用userDao完成
        return userDao.findAll();
    }
}

JDBCUtils

package cn.gtt.util;

import com.alibaba.druid.pool.DruidDataSourceFactory;

import javax.sql.DataSource;
import java.io.IOException;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;

/**
 * Druid连接池的工具类
 */
public class JDBCUtils {
//    定义成员变量DataSource
    private static DataSource dataSource;
    
    static {
        try {
//          加载配置文件
            Properties properties = new Properties();
            properties.load(JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties"));
//            获取DataSource
            dataSource= DruidDataSourceFactory.createDataSource(properties);
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * 获取连接
     */
    public  static Connection getConnection() throws SQLException {
        return  dataSource.getConnection();
    }

    /**
     * 释放资源
     */
    public  static  void  close(ResultSet resultSet,Statement statement, Connection connection){
        if(resultSet!=null){
            try {
                resultSet.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
        if(statement!=null){
            try {
                statement.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
        if(connection!=null){
            try {
                connection.close();
            } catch (SQLException throwables) {
                throwables.printStackTrace();
            }
        }
    }

    /**
     * 获取连接池方法
     */

    public  static  DataSource getDataSource(){
        return  dataSource;
    }




}

UserListServlet

package cn.gtt.web.servlet;


import cn.gtt.pojo.User;
import cn.gtt.service.Impl.UserServiceImpl;
import cn.gtt.service.UserService;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.List;

@WebServlet("/userListServlet")
public class UserListServlet  extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//        调用UserService完成查询
        UserService userService = new UserServiceImpl();
        List<User> users = userService.findAll();
//        将list存入request域
        req.setAttribute("users",users);
//        转发到list.jsp
        req.getRequestDispatcher("/list.jsp").forward(req,resp);
    }
}

index.jsp

<%--
  Created by IntelliJ IDEA.
  User: Lenovo
  Date: 2021/7/24
  Time: 20:37
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!DOCTYPE html>
<html >
<head>
  <meta charset="utf-8"/>
  <meta http-equiv="X-UA-Compatible" content="IE=edge"/>
  <meta name="viewport" content="width=device-width, initial-scale=1"/>
  <title>首页</title>

  <!-- 1. 导入CSS的全局样式 -->
  <link href="css/bootstrap.min.css" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  rel="stylesheet">
  <!-- 2. jQuery导入，建议使用1.9以上的版本 -->
  <script src="js/jquery-2.1.0.min.js"></script>
  <!-- 3. 导入bootstrap的js文件 -->
  <script src="js/bootstrap.min.js"></script>
  <script type="text/javascript">
  </script>
</head>
<body>
<div align="center">
  <a
<%--          ${pageContext.request.contextPath}来表示请求路径--%>
          href="${pageContext.request.contextPath}/userListServlet" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  style="text-decoration:none;font-size:33px">查询所有用户信息
  </a>
</div>
</body>
</html>

list.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<!-- 网页使用的语言 -->
<html >
<head>
    <!-- 指定字符集 -->
    <meta charset="utf-8">
    <!-- 使用Edge最新的浏览器的渲染方式 -->
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <!-- viewport视口：网页可以根据设置的宽度自动进行适配，在浏览器的内部虚拟一个容器，容器的宽度与设备的宽度相同。
    width: 默认宽度与设备的宽度相同
    initial-scale: 初始的缩放比，为1:1 -->
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <!-- 上述3个meta标签*必须*放在最前面，任何其他内容都*必须*跟随其后！ -->
    <title>用户信息管理系统</title>

    <!-- 1. 导入CSS的全局样式 -->
    <link href="css/bootstrap.min.css" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  rel="stylesheet">
    <!-- 2. jQuery导入，建议使用1.9以上的版本 -->
    <script src="js/jquery-2.1.0.min.js"></script>
    <!-- 3. 导入bootstrap的js文件 -->
    <script src="js/bootstrap.min.js"></script>
    <style type="text/css">
        td, th {
            text-align: center;
        }
    </style>
</head>
<body>
<div class="container">
    <h3 style="text-align: center">用户信息列表</h3>
    <table  class="table table-bordered table-hover">
        <tr class="success">
            <th>编号</th>
            <th>姓名</th>
            <th>性别</th>
            <th>年龄</th>
            <th>籍贯</th>
            <th>QQ</th>
            <th>邮箱</th>
            <th>操作</th>
        </tr>

        <c:forEach var="user"  varStatus="s" items="${users}">
            <tr>
                <td>${s.count}</td>
                <td>${user.name}</td>
                <td>${user.gender}</td>
                <td>${user.age}</td>
                <td>${user.address}</td>
                <td>${user.qq}</td>
                <td>${user.email}</td>
                <td><a class="btn btn-default btn-sm" href="update.html" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >修改</a>&nbsp;<a class="btn btn-default btn-sm" href="" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >删除</a></td>
            </tr>
        </c:forEach>

        <tr>
            <td colspan="8" align="center"><a class="btn btn-primary" href="add.html" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >添加联系人</a></td>
        </tr>
    </table>
</div>
</body>
</html>

3 页面调整

list.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<!-- 网页使用的语言 -->
<html >
<head>
    <!-- 指定字符集 -->
    <meta charset="utf-8">
    <!-- 使用Edge最新的浏览器的渲染方式 -->
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <!-- viewport视口：网页可以根据设置的宽度自动进行适配，在浏览器的内部虚拟一个容器，容器的宽度与设备的宽度相同。
    width: 默认宽度与设备的宽度相同
    initial-scale: 初始的缩放比，为1:1 -->
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <!-- 上述3个meta标签*必须*放在最前面，任何其他内容都*必须*跟随其后！ -->
    <title>用户信息管理系统</title>

    <!-- 1. 导入CSS的全局样式 -->
    <link href="css/bootstrap.min.css" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  rel="stylesheet">
    <!-- 2. jQuery导入，建议使用1.9以上的版本 -->
    <script src="js/jquery-2.1.0.min.js"></script>
    <!-- 3. 导入bootstrap的js文件 -->
    <script src="js/bootstrap.min.js"></script>
    <style type="text/css">
        td, th {
            text-align: center;
        }
    </style>
</head>
<body>
<div class="container">
    <h3 style="text-align: center">用户信息列表</h3>

    <div style="float:left;">
        <form class="form-inline">
            <div class="form-group">
                <label for="exampleInputName2">姓名</label>
                <input type="text" class="form-control" id="exampleInputName2">
            </div>
            <div class="form-group">
                <label for="exampleInputEmail2">籍贯</label>
                <input type="email" class="form-control" id="exampleInputEmail2" >
            </div>
            <div class="form-group">
                <label for="exampleInputEmail2">E-mail</label>
                <input type="email" class="form-control" id="exampleInputEmail2" >
            </div>
            <button type="submit" class="btn btn-default">查询</button>
        </form>
    </div>

    <div style="float: right;margin: 5px;">
        <a class="btn btn-primary" href="add.html" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >添加联系人</a>
        <a class="btn btn-primary" href="add.html" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >删除选中</a>
    </div>


    <table  class="table table-bordered table-hover">
        <tr class="success">
            <th><input type="checkbox"></th>
            <th>编号</th>
            <th>姓名</th>
            <th>性别</th>
            <th>年龄</th>
            <th>籍贯</th>
            <th>QQ</th>
            <th>邮箱</th>
            <th>操作</th>
        </tr>

        <c:forEach var="user"  varStatus="s" items="${users}">
            <tr>
                <td><input type="checkbox"></td>
                <td>${s.count}</td>
                <td>${user.name}</td>
                <td>${user.gender}</td>
                <td>${user.age}</td>
                <td>${user.address}</td>
                <td>${user.qq}</td>
                <td>${user.email}</td>
                <td><a class="btn btn-default btn-sm" href="update.html" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >修改</a>&nbsp;<a class="btn btn-default btn-sm" href="" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >删除</a></td>
            </tr>
        </c:forEach>

    </table>

    <div>
        <nav aria-label="Page navigation">
            <ul class="pagination">
                <li>
                    <a href="#" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  aria-label="Previous">
                        <span aria-hidden="true">&laquo;</span>
                    </a>
                </li>
                <li><a href="#" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >1</a></li>
                <li><a href="#" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >2</a></li>
                <li><a href="#" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >3</a></li>
                <li><a href="#" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >4</a></li>
                <li><a href="#" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >5</a></li>
                <li>
                    <a href="#" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  aria-label="Next">
                        <span aria-hidden="true">&raquo;</span>
                    </a>
                </li>
                <span style="font-size: 25px;margin-left: 20px">共16条记录,共4页</span>
            </ul>
        </nav>
    </div>
</div>
</body>
</html>

4 登录功能

验证码问题

login.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>

<!DOCTYPE html>
<html >
<head>
    <meta charset="utf-8"/>
    <meta http-equiv="X-UA-Compatible" content="IE=edge"/>
    <meta name="viewport" content="width=device-width, initial-scale=1"/>
    <title>管理员登录</title>

    <!-- 1. 导入CSS的全局样式 -->
    <link href="css/bootstrap.min.css" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  rel="stylesheet">
    <!-- 2. jQuery导入，建议使用1.9以上的版本 -->
    <script src="js/jquery-2.1.0.min.js"></script>
    <!-- 3. 导入bootstrap的js文件 -->
    <script src="js/bootstrap.min.js"></script>
    <script type="text/javascript">
        //切换验证码
        function refreshCode(){
            //1.获取验证码图片对象
            var vcode = document.getElementById("vcode");

            //2.设置其src属性，加时间戳
            vcode.src = "${pageContext.request.contextPath}/checkCodeServlet?time="+new Date().getTime();
        }
    </script>
</head>
<body>
<div class="container" style="width: 400px;">
    <h3 style="text-align: center;">管理员登录</h3>
    <form action="${pageContext.request.contextPath}/loginServlet" method="post">
        <div class="form-group">
            <label for="user">用户名：</label>
            <input type="text" name="username" class="form-control" id="user" placeholder="请输入用户名"/>
        </div>

        <div class="form-group">
            <label for="password">密码：</label>
            <input type="password" name="password" class="form-control" id="password" placeholder="请输入密码"/>
        </div>

        <div class="form-inline">
            <label for="vcode">验证码：</label>
            <input type="text" name="verifycode" class="form-control" id="verifycode" placeholder="请输入验证码" style="width: 120px;"/>
            <a href="javascript:refreshCode();" target="_blank" rel="external nofollow" >
                <img src="${pageContext.request.contextPath}/checkCodeServlet" title="看不清点击刷新" id="vcode"/>
            </a>
        </div>
        <hr/>
        <div class="form-group" style="text-align: center;">
            <input class="btn btn btn-primary" type="submit" value="登录">
        </div>
    </form>

    <!-- 出错显示的信息框 -->
    <div class="alert alert-warning alert-dismissible" role="alert">
        <button type="button" class="close" data-dismiss="alert" >
            <span>&times;</span>
        </button>
        <strong>${login_msg}</strong>
    </div>
</div>
</body>
</html>

index.jsp

<%--
  Created by IntelliJ IDEA.
  User: Lenovo
  Date: 2021/7/24
  Time: 20:37
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!DOCTYPE html>
<html >
<head>
  <meta charset="utf-8"/>
  <meta http-equiv="X-UA-Compatible" content="IE=edge"/>
  <meta name="viewport" content="width=device-width, initial-scale=1"/>
  <title>首页</title>

  <!-- 1. 导入CSS的全局样式 -->
  <link href="css/bootstrap.min.css" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  rel="stylesheet">
  <!-- 2. jQuery导入，建议使用1.9以上的版本 -->
  <script src="js/jquery-2.1.0.min.js"></script>
  <!-- 3. 导入bootstrap的js文件 -->
  <script src="js/bootstrap.min.js"></script>
  <script type="text/javascript">
  </script>
</head>
<body>
<div align="center">
  <a
<%--          ${pageContext.request.contextPath}来表示请求路径--%>
          href="${pageContext.request.contextPath}/userListServlet" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  style="text-decoration:none;font-size:33px">查询所有用户信息
  </a>
</div>
</body>
</html>

User

package cn.gtt.pojo;

public class User {
    private int id;
    private  String name;
    private  String gender;
    private int age;
    private  String address;
    private  String qq;
    private String email;

    private String username;
    private String password;

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public User(int id, String name, String gender, int age, String address, String qq, String email) {
        this.id = id;
        this.name = name;
        this.gender = gender;
        this.age = age;
        this.address = address;
        this.qq = qq;
        this.email = email;
    }

    public User() {
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }

    public String getQq() {
        return qq;
    }

    public void setQq(String qq) {
        this.qq = qq;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", gender='" + gender + '\'' +
                ", age=" + age +
                ", address='" + address + '\'' +
                ", qq='" + qq + '\'' +
                ", email='" + email + '\'' +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                '}';
    }
}

UserDao

package cn.gtt.dao;

import cn.gtt.pojo.User;

import java.util.List;

/**
 * 用户操作的dao
 */
public interface UserDao {
    /**
     * 查询所有用户信息
     */
    public List<User> findAll();

    /**
     * 登录
     * @param username
     * @param password
     * @return
     */
    User findUserByUsernamePassword(String username,String password);
}

UserDaoImpl

package cn.gtt.dao.Impl;

import cn.gtt.dao.UserDao;
import cn.gtt.pojo.User;
import cn.gtt.util.JDBCUtils;
import org.springframework.dao.EmptyResultDataAccessException;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;

import java.util.List;

public class UserDaoImpl implements UserDao {

    private  JdbcTemplate jdbcTemplate=new JdbcTemplate(JDBCUtils.getDataSource());
    /**
     * 查询所有用户信息
     */
    @Override
    public List<User> findAll() {
//        使用JDBC操作数据库
        String sql="select * from user";
        List<User> users = jdbcTemplate.query(sql, new BeanPropertyRowMapper<User>(User.class));
        return users;
    }

    /**
     * 登录
     * @param username
     * @param password
     * @return
     */
    @Override
    public User findUserByUsernamePassword(String username, String password) {
       try {
           String sql="select * from user where username=? and password=?";
           User user = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), username, password);
           return user;
       }catch (Exception e){
            e.printStackTrace();
            return  null;
       }
    }

}

UserService

package cn.gtt.service;

import cn.gtt.pojo.User;

import java.util.List;

/**
 * 用户管理的业务接口
 */
public interface UserService {
    /**
     * 查询所有用户信息
     * @return
     */
    public List<User> findAll();

    /**
     * 登录
     * @param user
     * @return
     */
    User login(User user);
}

UserServiceImpl

package cn.gtt.service.Impl;

import cn.gtt.dao.Impl.UserDaoImpl;
import cn.gtt.dao.UserDao;
import cn.gtt.pojo.User;
import cn.gtt.service.UserService;

import java.util.List;

public class UserServiceImpl implements UserService {

    UserDao userDao=new UserDaoImpl() ;
    /**
     * 查询所有用户信息
     */
    @Override
    public List<User> findAll() {
//        调用userDao完成
        return userDao.findAll();
    }

    /**
     * 登录
     * @param user
     * @return
     */
    @Override
    public User login(User user) {
        return userDao.findUserByUsernamePassword(user.getUsername(),user.getPassword());
    }
}

LoginServlet

package cn.gtt.web.servlet;

import cn.gtt.dao.Impl.UserDaoImpl;
import cn.gtt.pojo.User;
import cn.gtt.service.Impl.UserServiceImpl;
import cn.gtt.service.UserService;
import org.apache.commons.beanutils.BeanUtils;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.Map;

@WebServlet("/loginServlet")
public class LoginServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//        1.设置编码格式
        req.setCharacterEncoding("utf-8");

//        2.获取数据
//        2.1 获取用户填写验证码
        String verifycode = req.getParameter("verifycode");
//        3.验证码校验
        HttpSession session = req.getSession();
        String checkcode_server = (String) session.getAttribute("CHECKCODE_SERVER");
//        确保验证码一次性
        session.removeAttribute("CHECKCODE_SERVER");


        if (!checkcode_server.equalsIgnoreCase(verifycode)){
//            验证码不正确
//            提示信息
            req.setAttribute("login_msg","验证码错误！！！");
//            转跳登录页面
            req.getRequestDispatcher("/login.jsp").forward(req,resp);
            return;
        }
//        4.封装user对象
        Map<String, String[]> parameterMap = req.getParameterMap();
        User user=new User();
        try {
            BeanUtils.populate(user,parameterMap);
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }

//        5.调用service查询
        UserService userService = new UserServiceImpl();
        User login = userService.login(user);
//        6.判断是否登录成功
        if (login!=null){
//            将用户存入session
            session.setAttribute("user",login);
//            跳转页面
            resp.sendRedirect(req.getContextPath()+"/index.jsp");
        }else{
//            提示信息
            req.setAttribute("login_msg","用户名或密码错误！！！");
//            转跳登录页面
            req.getRequestDispatcher("/login.jsp").forward(req,resp);
        }


    }
}

5 添加功能

list.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<!-- 网页使用的语言 -->
<html >
<head>
    <!-- 指定字符集 -->
    <meta charset="utf-8">
    <!-- 使用Edge最新的浏览器的渲染方式 -->
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <!-- viewport视口：网页可以根据设置的宽度自动进行适配，在浏览器的内部虚拟一个容器，容器的宽度与设备的宽度相同。
    width: 默认宽度与设备的宽度相同
    initial-scale: 初始的缩放比，为1:1 -->
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <!-- 上述3个meta标签*必须*放在最前面，任何其他内容都*必须*跟随其后！ -->
    <title>用户信息管理系统</title>

    <!-- 1. 导入CSS的全局样式 -->
    <link href="css/bootstrap.min.css" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  rel="stylesheet">
    <!-- 2. jQuery导入，建议使用1.9以上的版本 -->
    <script src="js/jquery-2.1.0.min.js"></script>
    <!-- 3. 导入bootstrap的js文件 -->
    <script src="js/bootstrap.min.js"></script>
    <style type="text/css">
        td, th {
            text-align: center;
        }
    </style>
</head>
<body>
<div class="container">
    <h3 style="text-align: center">用户信息列表</h3>

    <div style="float:left;">
        <form class="form-inline">
            <div class="form-group">
                <label for="exampleInputName2">姓名</label>
                <input type="text" class="form-control" id="exampleInputName2">
            </div>
            <div class="form-group">
                <label for="exampleInputEmail2">籍贯</label>
                <input type="email" class="form-control" id="exampleInputEmail2" >
            </div>
            <div class="form-group">
                <label for="exampleInputEmail2">E-mail</label>
                <input type="email" class="form-control" id="exampleInputEmail2" >
            </div>
            <button type="submit" class="btn btn-default">查询</button>
        </form>
    </div>

    <div style="float: right;margin: 5px;">
        <a class="btn btn-primary" href="${pageContext.request.contextPath}/add.jsp" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >添加联系人</a>
        <a class="btn btn-primary" href="add.html" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >删除选中</a>
    </div>


    <table  class="table table-bordered table-hover">
        <tr class="success">
            <th><input type="checkbox"></th>
            <th>编号</th>
            <th>姓名</th>
            <th>性别</th>
            <th>年龄</th>
            <th>籍贯</th>
            <th>QQ</th>
            <th>邮箱</th>
            <th>操作</th>
        </tr>

        <c:forEach var="user"  varStatus="s" items="${users}">
            <tr>
                <td><input type="checkbox"></td>
                <td>${s.count}</td>
                <td>${user.name}</td>
                <td>${user.gender}</td>
                <td>${user.age}</td>
                <td>${user.address}</td>
                <td>${user.qq}</td>
                <td>${user.email}</td>
                <td><a class="btn btn-default btn-sm" href="update.html" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >修改</a>&nbsp;<a class="btn btn-default btn-sm" href="" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >删除</a></td>
            </tr>
        </c:forEach>

    </table>

    <div>
        <nav aria-label="Page navigation">
            <ul class="pagination">
                <li>
                    <a href="#" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  aria-label="Previous">
                        <span aria-hidden="true">&laquo;</span>
                    </a>
                </li>
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                <li><a href="#" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >5</a></li>
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                        <span aria-hidden="true">&raquo;</span>
                    </a>
                </li>
                <span style="font-size: 25px;margin-left: 20px">共16条记录,共4页</span>
            </ul>
        </nav>
    </div>
</div>
</body>
</html>

add.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>

<!-- HTML5文档-->
<!DOCTYPE html>
<!-- 网页使用的语言 -->
<html >
<head>
    <!-- 指定字符集 -->
    <meta charset="utf-8">
    <!-- 使用Edge最新的浏览器的渲染方式 -->
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <!-- viewport视口：网页可以根据设置的宽度自动进行适配，在浏览器的内部虚拟一个容器，容器的宽度与设备的宽度相同。
    width: 默认宽度与设备的宽度相同
    initial-scale: 初始的缩放比，为1:1 -->
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <!-- 上述3个meta标签*必须*放在最前面，任何其他内容都*必须*跟随其后！ -->
    <title>添加用户</title>

    <!-- 1. 导入CSS的全局样式 -->
    <link href="css/bootstrap.min.css" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  rel="stylesheet">
    <!-- 2. jQuery导入，建议使用1.9以上的版本 -->
    <script src="js/jquery-2.1.0.min.js"></script>
    <!-- 3. 导入bootstrap的js文件 -->
    <script src="js/bootstrap.min.js"></script>
</head>
<body>
<div class="container">
    <center><h3>添加联系人页面</h3></center>
    <form action="${pageContext.request.contextPath}/addUserServlet" method="post">
        <div class="form-group">
            <label for="name">姓名：</label>
            <input type="text" class="form-control" id="name" name="name" placeholder="请输入姓名">
        </div>

        <div class="form-group">
            <label>性别：</label>
            <input type="radio" name="gender" value="男" checked="checked"/>男
            <input type="radio" name="gender" value="女"/>女
        </div>

        <div class="form-group">
            <label for="age">年龄：</label>
            <input type="text" class="form-control" id="age" name="age" placeholder="请输入年龄">
        </div>

        <div class="form-group">
            <label for="address">籍贯：</label>
            <select name="address" class="form-control" id="address">
                <option value="陕西">陕西</option>
                <option value="北京">北京</option>
                <option value="上海">上海</option>
            </select>
        </div>

        <div class="form-group">
            <label for="qq">QQ：</label>
            <input type="text" class="form-control" id="qq" name="qq" placeholder="请输入QQ号码"/>
        </div>

        <div class="form-group">
            <label for="email">Email：</label>
            <input type="text" class="form-control" id="email" name="email" placeholder="请输入邮箱地址"/>
        </div>

        <div class="form-group" style="text-align: center">
            <input class="btn btn-primary" type="submit" value="提交" />
            <input class="btn btn-default" type="reset" value="重置" />
            <input class="btn btn-default" type="button" value="返回" />
        </div>
    </form>
</div>
</body>
</html>

UserDao

package cn.gtt.dao;

import cn.gtt.pojo.User;

import java.util.List;

/**
 * 用户操作的dao
 */
public interface UserDao {
    /**
     * 查询所有用户信息
     */
    public List<User> findAll();

    /**
     * 登录
     * @param username
     * @param password
     * @return
     */
    User findUserByUsernamePassword(String username,String password);

    /**
     * 添加
     * @param user
     */
    public  void  addUser(User user);
}

UserDaoImpl

package cn.gtt.dao.Impl;

import cn.gtt.dao.UserDao;
import cn.gtt.pojo.User;
import cn.gtt.util.JDBCUtils;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;

import java.util.List;

public class UserDaoImpl implements UserDao {

    private  JdbcTemplate jdbcTemplate=new JdbcTemplate(JDBCUtils.getDataSource());
    /**
     * 查询所有用户信息
     */
    @Override
    public List<User> findAll() {
//        使用JDBC操作数据库
        String sql="select * from user";
        List<User> users = jdbcTemplate.query(sql, new BeanPropertyRowMapper<User>(User.class));
        return users;
    }

    /**
     * 登录
     * @param username
     * @param password
     * @return
     */
    @Override
    public User findUserByUsernamePassword(String username, String password) {
       try {
           String sql="select * from user where username=? and password=?";
           User user = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), username, password);
           return user;
       }catch (Exception e){
            e.printStackTrace();
            return  null;
       }
    }

    /**
     * 添加
     * @param user
     */
    @Override
    public void addUser(User user) {
        String sql="insert into user values(null,?,?,?,?,?,?,null,null)";
        jdbcTemplate.update(sql,user.getName(),user.getGender(),user.getAge(),user.getAddress(),user.getQq(),user.getEmail());
    }

}

UserService

package cn.gtt.service;

import cn.gtt.pojo.User;

import java.util.List;

/**
 * 用户管理的业务接口
 */
public interface UserService {
    /**
     * 查询所有用户信息
     * @return
     */
    public List<User> findAll();

    /**
     * 登录
     * @param user
     * @return
     */
    User login(User user);

    /**
     * 添加
     * @param user
     */
    void addUser(User user);
}

UserServiceImpl

package cn.gtt.service.Impl;

import cn.gtt.dao.Impl.UserDaoImpl;
import cn.gtt.dao.UserDao;
import cn.gtt.pojo.User;
import cn.gtt.service.UserService;

import java.util.List;

public class UserServiceImpl implements UserService {

    UserDao userDao=new UserDaoImpl() ;
    /**
     * 查询所有用户信息
     */
    @Override
    public List<User> findAll() {
//        调用userDao完成
        return userDao.findAll();
    }

    /**
     * 登录
     * @param user
     * @return
     */
    @Override
    public User login(User user) {
        return userDao.findUserByUsernamePassword(user.getUsername(),user.getPassword());
    }

    /**
     * 添加
     * @param user
     */
    @Override
    public void addUser(User user) {
        userDao.addUser(user);
    }
}

AddUserServlet

package cn.gtt.web.servlet;

import cn.gtt.pojo.User;
import cn.gtt.service.Impl.UserServiceImpl;
import cn.gtt.service.UserService;
import org.apache.commons.beanutils.BeanUtils;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.Map;

@WebServlet("/addUserServlet")
public class AddUserServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//        1.设置编码格式
        req.setCharacterEncoding("utf-8");
        
//        获取参数
        Map<String, String[]> parameterMap = req.getParameterMap();

//        封装对象
        User user=new User();
        try {
            BeanUtils.populate(user,parameterMap);
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }

//        调用service保存
        UserService userService=new UserServiceImpl();
        userService.addUser(user);

//        转跳到userListServlet
        resp.sendRedirect(req.getContextPath()+"/userListServlet");
    }
}

6 删除

list.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<!-- 网页使用的语言 -->
<html >
<head>
    <!-- 指定字符集 -->
    <meta charset="utf-8">
    <!-- 使用Edge最新的浏览器的渲染方式 -->
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <!-- viewport视口：网页可以根据设置的宽度自动进行适配，在浏览器的内部虚拟一个容器，容器的宽度与设备的宽度相同。
    width: 默认宽度与设备的宽度相同
    initial-scale: 初始的缩放比，为1:1 -->
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <!-- 上述3个meta标签*必须*放在最前面，任何其他内容都*必须*跟随其后！ -->
    <title>用户信息管理系统</title>

    <!-- 1. 导入CSS的全局样式 -->
    <link href="css/bootstrap.min.css" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  rel="stylesheet">
    <!-- 2. jQuery导入，建议使用1.9以上的版本 -->
    <script src="js/jquery-2.1.0.min.js"></script>
    <!-- 3. 导入bootstrap的js文件 -->
    <script src="js/bootstrap.min.js"></script>
    <style type="text/css">
        td, th {
            text-align: center;
        }
    </style>
    <script>
        function  deleteUser(id){
            // 用户安全显示
            if(confirm("您确定要删除么？")){
                // 访问路径
                location.href=" ${pageContext.request.contextPath}/delUserServlet?id=" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" +id;
            }
        }


    </script>
</head>
<body>
<div class="container">
    <h3 style="text-align: center">用户信息列表</h3>

    <div style="float:left;">
        <form class="form-inline">
            <div class="form-group">
                <label for="exampleInputName2">姓名</label>
                <input type="text" class="form-control" id="exampleInputName2">
            </div>
            <div class="form-group">
                <label for="exampleInputEmail2">籍贯</label>
                <input type="email" class="form-control" id="exampleInputEmail2" >
            </div>
            <div class="form-group">
                <label for="exampleInputEmail2">E-mail</label>
                <input type="email" class="form-control" id="exampleInputEmail2" >
            </div>
            <button type="submit" class="btn btn-default">查询</button>
        </form>
    </div>

    <div style="float: right;margin: 5px;">
        <a class="btn btn-primary" href="${pageContext.request.contextPath}/add.jsp" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >添加联系人</a>
        <a class="btn btn-primary" href="" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >删除选中</a>
    </div>


    <table  class="table table-bordered table-hover">
        <tr class="success">
            <th><input type="checkbox"></th>
            <th>编号</th>
            <th>姓名</th>
            <th>性别</th>
            <th>年龄</th>
            <th>籍贯</th>
            <th>QQ</th>
            <th>邮箱</th>
            <th>操作</th>
        </tr>

        <c:forEach var="user"  varStatus="s" items="${users}">
            <tr>
                <td><input type="checkbox"></td>
                <td>${s.count}</td>
                <td>${user.name}</td>
                <td>${user.gender}</td>
                <td>${user.age}</td>
                <td>${user.address}</td>
                <td>${user.qq}</td>
                <td>${user.email}</td>
                <td>
                    <a class="btn btn-default btn-sm" href="update.html" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >修改</a>&nbsp;
                    <a class="btn btn-default btn-sm" href="javascript:deleteUser(${user.id});" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >删除</a></td>
            </tr>
        </c:forEach>

    </table>

    <div>
        <nav aria-label="Page navigation">
            <ul class="pagination">
                <li>
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                        <span aria-hidden="true">&laquo;</span>
                    </a>
                </li>
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                <span style="font-size: 25px;margin-left: 20px">共16条记录,共4页</span>
            </ul>
        </nav>
    </div>
</div>
</body>
</html>

UserDao

package cn.gtt.dao;

import cn.gtt.pojo.User;

import java.util.List;

/**
 * 用户操作的dao
 */
public interface UserDao {
    /**
     * 查询所有用户信息
     */
    public List<User> findAll();

    /**
     * 登录
     * @param username
     * @param password
     * @return
     */
    User findUserByUsernamePassword(String username,String password);

    /**
     * 添加
     * @param user
     */
    public  void  addUser(User user);

    /**
     * 删除
     * @param id
     */
    public  void  deleteUser(int id);
}

UserDaoImpl

package cn.gtt.dao.Impl;

import cn.gtt.dao.UserDao;
import cn.gtt.pojo.User;
import cn.gtt.util.JDBCUtils;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;

import java.util.List;

public class UserDaoImpl implements UserDao {

    private  JdbcTemplate jdbcTemplate=new JdbcTemplate(JDBCUtils.getDataSource());
    /**
     * 查询所有用户信息
     */
    @Override
    public List<User> findAll() {
//        使用JDBC操作数据库
        String sql="select * from user";
        List<User> users = jdbcTemplate.query(sql, new BeanPropertyRowMapper<User>(User.class));
        return users;
    }

    /**
     * 登录
     * @param username
     * @param password
     * @return
     */
    @Override
    public User findUserByUsernamePassword(String username, String password) {
       try {
           String sql="select * from user where username=? and password=?";
           User user = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), username, password);
           return user;
       }catch (Exception e){
            e.printStackTrace();
            return  null;
       }
    }

    /**
     * 添加
     * @param user
     */
    @Override
    public void addUser(User user) {
        String sql="insert into user values(null,?,?,?,?,?,?,null,null)";
        jdbcTemplate.update(sql,user.getName(),user.getGender(),user.getAge(),user.getAddress(),user.getQq(),user.getEmail());
    }

    /**
     * 删除
     */
    @Override
    public void deleteUser(int id) {
        String sql="delete from user where id=?";
        jdbcTemplate.update(sql,id);
    }

}

UserService

package cn.gtt.service;

import cn.gtt.pojo.User;

import java.util.List;

/**
 * 用户管理的业务接口
 */
public interface UserService {
    /**
     * 查询所有用户信息
     * @return
     */
    public List<User> findAll();

    /**
     * 登录
     * @param user
     * @return
     */
    User login(User user);

    /**
     * 添加
     * @param user
     */
    void addUser(User user);

    /**
     * 删除
     */
    void deleteUser(String id);
}

UserServiceImpl

package cn.gtt.service.Impl;

import cn.gtt.dao.Impl.UserDaoImpl;
import cn.gtt.dao.UserDao;
import cn.gtt.pojo.User;
import cn.gtt.service.UserService;

import java.util.List;

public class UserServiceImpl implements UserService {

    UserDao userDao=new UserDaoImpl() ;
    /**
     * 查询所有用户信息
     */
    @Override
    public List<User> findAll() {
//        调用userDao完成
        return userDao.findAll();
    }

    /**
     * 登录
     * @param user
     * @return
     */
    @Override
    public User login(User user) {
        return userDao.findUserByUsernamePassword(user.getUsername(),user.getPassword());
    }

    /**
     * 添加
     * @param user
     */
    @Override
    public void addUser(User user) {
        userDao.addUser(user);
    }

    @Override
    public void deleteUser(String id) {
        userDao.deleteUser(Integer.parseInt(id));
    }
}

DelUserServlet

package cn.gtt.web.servlet;

import cn.gtt.service.Impl.UserServiceImpl;
import cn.gtt.service.UserService;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebServlet("/delUserServlet")
public class DelUserServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//        获取id
        String id = req.getParameter("id");
//        调用service层删除
        UserService userService=new UserServiceImpl();
        userService.deleteUser(id);
//        转跳到查询所有servlet
        resp.sendRedirect(req.getContextPath()+"/userListServlet");




    }
}

7 修改

list.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<!-- 网页使用的语言 -->
<html >
<head>
    <!-- 指定字符集 -->
    <meta charset="utf-8">
    <!-- 使用Edge最新的浏览器的渲染方式 -->
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <!-- viewport视口：网页可以根据设置的宽度自动进行适配，在浏览器的内部虚拟一个容器，容器的宽度与设备的宽度相同。
    width: 默认宽度与设备的宽度相同
    initial-scale: 初始的缩放比，为1:1 -->
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <!-- 上述3个meta标签*必须*放在最前面，任何其他内容都*必须*跟随其后！ -->
    <title>用户信息管理系统</title>

    <!-- 1. 导入CSS的全局样式 -->
    <link href="css/bootstrap.min.css" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  rel="stylesheet">
    <!-- 2. jQuery导入，建议使用1.9以上的版本 -->
    <script src="js/jquery-2.1.0.min.js"></script>
    <!-- 3. 导入bootstrap的js文件 -->
    <script src="js/bootstrap.min.js"></script>
    <style type="text/css">
        td, th {
            text-align: center;
        }
    </style>
    <script>
        function  deleteUser(id){
            // 用户安全显示
            if(confirm("您确定要删除么？")){
                // 访问路径
                location.href=" ${pageContext.request.contextPath}/delUserServlet?id=" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" +id;
            }
        }


    </script>
</head>
<body>
<div class="container">
    <h3 style="text-align: center">用户信息列表</h3>

    <div style="float:left;">
        <form class="form-inline">
            <div class="form-group">
                <label for="exampleInputName2">姓名</label>
                <input type="text" class="form-control" id="exampleInputName2">
            </div>
            <div class="form-group">
                <label for="exampleInputEmail2">籍贯</label>
                <input type="email" class="form-control" id="exampleInputEmail2" >
            </div>
            <div class="form-group">
                <label for="exampleInputEmail2">E-mail</label>
                <input type="email" class="form-control" id="exampleInputEmail2" >
            </div>
            <button type="submit" class="btn btn-default">查询</button>
        </form>
    </div>

    <div style="float: right;margin: 5px;">
        <a class="btn btn-primary" href="${pageContext.request.contextPath}/add.jsp" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >添加联系人</a>
        <a class="btn btn-primary" href="" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >删除选中</a>
    </div>


    <table  class="table table-bordered table-hover">
        <tr class="success">
            <th><input type="checkbox"></th>
            <th>编号</th>
            <th>姓名</th>
            <th>性别</th>
            <th>年龄</th>
            <th>籍贯</th>
            <th>QQ</th>
            <th>邮箱</th>
            <th>操作</th>
        </tr>

        <c:forEach var="user"  varStatus="s" items="${users}">
            <tr>
                <td><input type="checkbox"></td>
                <td>${s.count}</td>
                <td>${user.name}</td>
                <td>${user.gender}</td>
                <td>${user.age}</td>
                <td>${user.address}</td>
                <td>${user.qq}</td>
                <td>${user.email}</td>
                <td>
                    <a class="btn btn-default btn-sm" href="${pageContext.request.contextPath}/findUserServlet?id=${user.id}" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >修改</a>&nbsp;
                    <a class="btn btn-default btn-sm" href="javascript:deleteUser(${user.id});" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >删除</a></td>
            </tr>
        </c:forEach>

    </table>

    <div>
        <nav aria-label="Page navigation">
            <ul class="pagination">
                <li>
                    <a href="#" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  aria-label="Previous">
                        <span aria-hidden="true">&laquo;</span>
                    </a>
                </li>
                <li><a href="#" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >1</a></li>
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                    </a>
                </li>
                <span style="font-size: 25px;margin-left: 20px">共16条记录,共4页</span>
            </ul>
        </nav>
    </div>
</div>
</body>
</html>

update.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<!-- 网页使用的语言 -->
<html >
    <head>
        <!-- 指定字符集 -->
        <meta charset="utf-8">
        <meta http-equiv="X-UA-Compatible" content="IE=edge">
        <meta name="viewport" content="width=device-width, initial-scale=1">
        <title>修改用户</title>

        <link href="css/bootstrap.min.css" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  rel="stylesheet">
        <script src="js/jquery-2.1.0.min.js"></script>
        <script src="js/bootstrap.min.js"></script>
        
    </head>
    <body>
        <div class="container" style="width: 400px;">
        <h3 style="text-align: center;">修改联系人</h3>
        <form action="${pageContext.request.contextPath}/updateUserServlet" method="post">
            <!--  隐藏域 提交id-->
            <input type="hidden" name="id" value="${user.id}">

          <div class="form-group">
            <label for="name">姓名：</label>
            <input type="text" class="form-control" id="name" name="name"  value="${user.name}" readonly="readonly" placeholder="请输入姓名" />
          </div>

          <div class="form-group">
            <label>性别：</label>
              <c:if test="${user.gender == '男'}">
                  <input type="radio" name="gender" value="男" checked />男
                  <input type="radio" name="gender" value="女"  />女
              </c:if>

              <c:if test="${user.gender == '女'}">
                  <input type="radio" name="gender" value="男"  />男
                  <input type="radio" name="gender" value="女" checked  />女
              </c:if>


          </div>

          <div class="form-group">
            <label for="age">年龄：</label>
            <input type="text" class="form-control" value="${user.age}" id="age"  name="age" placeholder="请输入年龄" />
          </div>

          <div class="form-group">
            <label for="address">籍贯：</label>
             <select name="address" id="address" class="form-control" >
                 <c:if test="${user.address == '陕西'}">
                    <option value="陕西" selected>陕西</option>
                    <option value="北京">北京</option>
                    <option value="上海">上海</option>
                 </c:if>

                 <c:if test="${user.address == '北京'}">
                     <option value="陕西" >陕西</option>
                     <option value="北京" selected>北京</option>
                     <option value="上海">上海</option>
                 </c:if>

                 <c:if test="${user.address == '上海'}">
                     <option value="陕西" >陕西</option>
                     <option value="北京">北京</option>
                     <option value="上海" selected>上海</option>
                 </c:if>
            </select>
          </div>

          <div class="form-group">
            <label for="qq">QQ：</label>
            <input type="text" id="qq" class="form-control" value="${user.qq}" name="qq" placeholder="请输入QQ号码"/>
          </div>

          <div class="form-group">
            <label for="email">Email：</label>
            <input type="text" id="email" class="form-control" value="${user.email}" name="email" placeholder="请输入邮箱地址"/>
          </div>

             <div class="form-group" style="text-align: center">
                <input class="btn btn-primary" type="submit" value="提交" />
                <input class="btn btn-default" type="reset" value="重置" />
                <input class="btn btn-default" type="button" value="返回"/>
             </div>
        </form>
        </div>
    </body>
</html>

UserDao

package cn.gtt.dao;

import cn.gtt.pojo.User;

import java.util.List;

/**
 * 用户操作的dao
 */
public interface UserDao {
    /**
     * 查询所有用户信息
     */
    public List<User> findAll();

    /**
     * 登录
     * @param username
     * @param password
     * @return
     */
    User findUserByUsernamePassword(String username,String password);

    /**
     * 添加
     * @param user
     */
    public  void  addUser(User user);

    /**
     * 删除
     * @param id
     */
    public  void  deleteUser(int id);

    /**
     * 修改
     */
    User findUserById(int id);
   public void updateUser(User user);
}

UserDaoImpl

package cn.gtt.dao.Impl;

import cn.gtt.dao.UserDao;
import cn.gtt.pojo.User;
import cn.gtt.util.JDBCUtils;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;

import java.util.List;

public class UserDaoImpl implements UserDao {

    private  JdbcTemplate jdbcTemplate=new JdbcTemplate(JDBCUtils.getDataSource());
    /**
     * 查询所有用户信息
     */
    @Override
    public List<User> findAll() {
//        使用JDBC操作数据库
        String sql="select * from user";
        List<User> users = jdbcTemplate.query(sql, new BeanPropertyRowMapper<User>(User.class));
        return users;
    }

    /**
     * 登录
     * @param username
     * @param password
     * @return
     */
    @Override
    public User findUserByUsernamePassword(String username, String password) {
       try {
           String sql="select * from user where username=? and password=?";
           User user = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), username, password);
           return user;
       }catch (Exception e){
            e.printStackTrace();
            return  null;
       }
    }

    /**
     * 添加
     * @param user
     */
    @Override
    public void addUser(User user) {
        String sql="insert into user values(null,?,?,?,?,?,?,null,null)";
        jdbcTemplate.update(sql,user.getName(),user.getGender(),user.getAge(),user.getAddress(),user.getQq(),user.getEmail());
    }

    /**
     * 删除
     */
    @Override
    public void deleteUser(int id) {
        String sql="delete from user where id=?";
        jdbcTemplate.update(sql,id);
    }

    /**
     * 修改
     * @param id
     */
    @Override
    public User findUserById(int id) {
        String sql="select * from  user where id=?";
        User user = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), id);
        return user;
    }

    @Override
    public void updateUser(User user) {
        String sql="update  user set name=?,gender=?,age=?,address=?,qq=?,email=?  where id=?";
        jdbcTemplate.update(sql, user.getName(), user.getGender(), user.getAge(), user.getAddress(), user.getQq(), user.getEmail(), user.getId());
    }

}

UserService

package cn.gtt.service;

import cn.gtt.pojo.User;

import java.util.List;

/**
 * 用户管理的业务接口
 */
public interface UserService {
    /**
     * 查询所有用户信息
     * @return
     */
    public List<User> findAll();

    /**
     * 登录
     * @param user
     * @return
     */
    User login(User user);

    /**
     * 添加
     * @param user
     */
    void addUser(User user);

    /**
     * 删除
     */
    void deleteUser(String id);

    /**
     * 修改
     */
    User  findUserById(String id);
    public void updateUser(User user);

}

UserServiceImpl

package cn.gtt.service.Impl;

import cn.gtt.dao.Impl.UserDaoImpl;
import cn.gtt.dao.UserDao;
import cn.gtt.pojo.User;
import cn.gtt.service.UserService;

import java.util.List;

public class UserServiceImpl implements UserService {

    UserDao userDao=new UserDaoImpl() ;
    /**
     * 查询所有用户信息
     */
    @Override
    public List<User> findAll() {
//        调用userDao完成
        return userDao.findAll();
    }

    /**
     * 登录
     * @param user
     * @return
     */
    @Override
    public User login(User user) {
        return userDao.findUserByUsernamePassword(user.getUsername(),user.getPassword());
    }

    /**
     * 添加
     * @param user
     */
    @Override
    public void addUser(User user) {
        userDao.addUser(user);
    }

    /**
     * 删除
     * @param id
     */
    @Override
    public void deleteUser(String id) {
        userDao.deleteUser(Integer.parseInt(id));
    }

    /**
     * 修改
     * @param id
     */
    @Override
    public User findUserById(String id) {
        return userDao.findUserById(Integer.parseInt(id));
    }

    @Override
    public void updateUser(User user) {
        userDao.updateUser(user);
    }
}

FindUserServlet

package cn.gtt.web.servlet;

import cn.gtt.pojo.User;
import cn.gtt.service.Impl.UserServiceImpl;
import cn.gtt.service.UserService;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebServlet("/findUserServlet")
public class FindUserServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("utf-8");

//        获取id
        String id = req.getParameter("id");
//        调用service查询
        UserService userService=new UserServiceImpl();
        User user=userService.findUserById(id);

//        将user存入request
            req.setAttribute("user",user);
            req.getRequestDispatcher("/update.jsp").forward(req,resp);

    }
}

UpdateUserServlet

package cn.gtt.web.servlet;

import cn.gtt.pojo.User;
import cn.gtt.service.Impl.UserServiceImpl;
import cn.gtt.service.UserService;
import org.apache.commons.beanutils.BeanUtils;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.Map;

@WebServlet("/updateUserServlet")
public class UpdateUserServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("utf-8");
//        获取map
        Map<String, String[]> parameterMap = req.getParameterMap();
//        封装对象
        User user=new User();
        try {
            BeanUtils.populate(user,parameterMap);
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }
//        调用service保存
        UserService userService=new UserServiceImpl();
        userService.updateUser(user);

//        转跳到userListServlet
        resp.sendRedirect(req.getContextPath()+"/userListServlet");
    }
}

8 删除选中功能

list.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<!-- 网页使用的语言 -->
<html >
<head>
    <!-- 指定字符集 -->
    <meta charset="utf-8">
    <!-- 使用Edge最新的浏览器的渲染方式 -->
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <!-- viewport视口：网页可以根据设置的宽度自动进行适配，在浏览器的内部虚拟一个容器，容器的宽度与设备的宽度相同。
    width: 默认宽度与设备的宽度相同
    initial-scale: 初始的缩放比，为1:1 -->
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <!-- 上述3个meta标签*必须*放在最前面，任何其他内容都*必须*跟随其后！ -->
    <title>用户信息管理系统</title>

    <!-- 1. 导入CSS的全局样式 -->
    <link href="css/bootstrap.min.css" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  rel="stylesheet">
    <!-- 2. jQuery导入，建议使用1.9以上的版本 -->
    <script src="js/jquery-2.1.0.min.js"></script>
    <!-- 3. 导入bootstrap的js文件 -->
    <script src="js/bootstrap.min.js"></script>
    <style type="text/css">
        td, th {
            text-align: center;
        }
    </style>
    <script>
        function  deleteUser(id){
            // 用户安全显示
            if(confirm("您确定要删除么？")){
                // 访问路径
                location.href=" ${pageContext.request.contextPath}/delUserServlet?id=" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" +id;
            }
        }

        window.onload=function (){
            // 给删除选中按钮添加单击事件
            document.getElementById("delSelected").onclick=function (){
                if(confirm("您确定要删除选中条目吗？")){

                    var flag = false;
                    //判断是否有选中条目
                    var cbs = document.getElementsByName("uid");
                    for (var i = 0; i < cbs.length; i++) {
                        if(cbs[i].checked){
                            //有一个条目选中了
                            flag = true;
                            break;
                        }
                    }

                    if(flag){//有条目被选中
                        //表单提交
                        document.getElementById("form").submit();
                    }

                }
            }

            //1.获取第一个cb
            document.getElementById("firstCb").onclick = function(){
                //2.获取下边列表中所有的cb
                var cbs = document.getElementsByName("uid");
                //3.遍历
                for (var i = 0; i < cbs.length; i++) {
                    //4.设置这些cbs[i]的checked状态 = firstCb.checked
                    cbs[i].checked = this.checked;

                }

            }
        }


    </script>
</head>
<body>
<div class="container">
    <h3 style="text-align: center">用户信息列表</h3>

    <div style="float:left;">
        <form class="form-inline">
            <div class="form-group">
                <label for="exampleInputName2">姓名</label>
                <input type="text" class="form-control" id="exampleInputName2">
            </div>
            <div class="form-group">
                <label for="exampleInputEmail3">籍贯</label>
                <input type="email" class="form-control" id="exampleInputEmail3" >
            </div>
            <div class="form-group">
                <label for="exampleInputEmail4">E-mail</label>
                <input type="email" class="form-control" id="exampleInputEmail4" >
            </div>
            <button type="submit" class="btn btn-default">查询</button>
        </form>
    </div>

    <div style="float: right;margin: 5px;">
        <a class="btn btn-primary" href="${pageContext.request.contextPath}/add.jsp" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >添加联系人</a>
        <a class="btn btn-primary" href="javascript:void(0);" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  id="delSelected">删除选中</a>
    </div>

    <form action="${pageContext.request.contextPath}/delSelectedServlet" method="post" id="form">
        <table  class="table table-bordered table-hover">
            <tr class="success">
                <th><input type="checkbox" id="firstCb"></th>
                <th>编号</th>
                <th>姓名</th>
                <th>性别</th>
                <th>年龄</th>
                <th>籍贯</th>
                <th>QQ</th>
                <th>邮箱</th>
                <th>操作</th>
            </tr>

            <c:forEach var="user"  varStatus="s" items="${users}">
                <tr>
                    <td><input type="checkbox" name="uid" value="${user.id}"></td>
                    <td>${s.count}</td>
                    <td>${user.name}</td>
                    <td>${user.gender}</td>
                    <td>${user.age}</td>
                    <td>${user.address}</td>
                    <td>${user.qq}</td>
                    <td>${user.email}</td>
                    <td>
                        <a class="btn btn-default btn-sm" href="${pageContext.request.contextPath}/findUserServlet?id=${user.id}" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >修改</a>&nbsp;
                        <a class="btn btn-default btn-sm" href="javascript:deleteUser(${user.id});" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >删除</a></td>
                </tr>
            </c:forEach>

        </table>
    </form>

    <div>
        <nav aria-label="Page navigation">
            <ul class="pagination">
                <li>
                    <a href="#" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  aria-label="Previous">
                        <span aria-hidden="true">&laquo;</span>
                    </a>
                </li>
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                <li><a href="#" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >4</a></li>
                <li><a href="#" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >5</a></li>
                <li>
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                        <span aria-hidden="true">&raquo;</span>
                    </a>
                </li>
                <span style="font-size: 25px;margin-left: 20px">共16条记录,共4页</span>
            </ul>
        </nav>
    </div>
</div>
</body>
</html>

UserService

package cn.gtt.service;

import cn.gtt.pojo.User;

import java.util.List;

/**
 * 用户管理的业务接口
 */
public interface UserService {
    /**
     * 查询所有用户信息
     * @return
     */
    public List<User> findAll();

    /**
     * 登录
     * @param user
     * @return
     */
    User login(User user);

    /**
     * 添加
     * @param user
     */
    void addUser(User user);

    /**
     * 删除
     */
    void deleteUser(String id);

    /**
     * 修改
     */
    User  findUserById(String id);
    public void updateUser(User user);

    /**
     * 删除选中
     */
     void delSelecteUser(String[] ids);

}

UserServiceImpl

package cn.gtt.service.Impl;

import cn.gtt.dao.Impl.UserDaoImpl;
import cn.gtt.dao.UserDao;
import cn.gtt.pojo.User;
import cn.gtt.service.UserService;

import java.util.List;

public class UserServiceImpl implements UserService {

    UserDao userDao=new UserDaoImpl() ;
    /**
     * 查询所有用户信息
     */
    @Override
    public List<User> findAll() {
//        调用userDao完成
        return userDao.findAll();
    }

    /**
     * 登录
     * @param user
     * @return
     */
    @Override
    public User login(User user) {
        return userDao.findUserByUsernamePassword(user.getUsername(),user.getPassword());
    }

    /**
     * 添加
     * @param user
     */
    @Override
    public void addUser(User user) {
        userDao.addUser(user);
    }

    /**
     * 删除
     * @param id
     */
    @Override
    public void deleteUser(String id) {
        userDao.deleteUser(Integer.parseInt(id));
    }

    /**
     * 修改
     * @param id
     */
    @Override
    public User findUserById(String id) {
        return userDao.findUserById(Integer.parseInt(id));
    }

    @Override
    public void updateUser(User user) {
        userDao.updateUser(user);
    }

    /**
     * 删除选中
     * @param ids
     */
    @Override
    public void delSelecteUser(String[] ids) {
        if(ids != null && ids.length > 0){
            //1.遍历数组
            for (String id : ids) {
                //2.调用dao删除
                userDao.deleteUser(Integer.parseInt(id));
            }
        }
    }



}

DelSelectedServlet

package cn.gtt.web.servlet;

import cn.gtt.service.Impl.UserServiceImpl;
import cn.gtt.service.UserService;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebServlet("/delSelectedServlet")
public class DelSelectedServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//        获取所有的id
        String[] uids = req.getParameterValues("uid");
//        调用service删除
        UserService userService=new UserServiceImpl();
        userService.delSelecteUser(uids);
        resp.sendRedirect(req.getContextPath()+"/userListServlet");

    }
}

9 分页

减轻服务器内存的开销
提升用户体验

index.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

<!DOCTYPE html>
<html >
<head>
  <meta charset="utf-8"/>
  <meta http-equiv="X-UA-Compatible" content="IE=edge"/>
  <meta name="viewport" content="width=device-width, initial-scale=1"/>
  <title>首页</title>

  <!-- 1. 导入CSS的全局样式 -->
  <link href="css/bootstrap.min.css" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  rel="stylesheet">
  <!-- 2. jQuery导入，建议使用1.9以上的版本 -->
  <script src="js/jquery-2.1.0.min.js"></script>
  <!-- 3. 导入bootstrap的js文件 -->
  <script src="js/bootstrap.min.js"></script>
  <script type="text/javascript">
  </script>
</head>
<body>


  <div >${user.name},欢迎您</div>
  <div align="center">
    <a
            href="${pageContext.request.contextPath}/findUserByPageServlet" target="_blank" rel="external nofollow"  style="text-decoration:none;font-size:33px">查询所有用户信息
    </a>
  </div>






</body>
</html>

list.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<!-- 网页使用的语言 -->
<html >
<head>
    <!-- 指定字符集 -->
    <meta charset="utf-8">
    <!-- 使用Edge最新的浏览器的渲染方式 -->
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <!-- viewport视口：网页可以根据设置的宽度自动进行适配，在浏览器的内部虚拟一个容器，容器的宽度与设备的宽度相同。
    width: 默认宽度与设备的宽度相同
    initial-scale: 初始的缩放比，为1:1 -->
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <!-- 上述3个meta标签*必须*放在最前面，任何其他内容都*必须*跟随其后！ -->
    <title>用户信息管理系统</title>

    <!-- 1. 导入CSS的全局样式 -->
    <link href="css/bootstrap.min.css" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  rel="stylesheet">
    <!-- 2. jQuery导入，建议使用1.9以上的版本 -->
    <script src="js/jquery-2.1.0.min.js"></script>
    <!-- 3. 导入bootstrap的js文件 -->
    <script src="js/bootstrap.min.js"></script>
    <style type="text/css">
        td, th {
            text-align: center;
        }
    </style>
    <script>
        function  deleteUser(id){
            // 用户安全显示
            if(confirm("您确定要删除么？")){
                // 访问路径
                location.href=" ${pageContext.request.contextPath}/delUserServlet?id=" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" +id;
            }
        }

        window.onload=function (){
            // 给删除选中按钮添加单击事件
            document.getElementById("delSelected").onclick=function (){
                if(confirm("您确定要删除选中条目吗？")){

                    var flag = false;
                    //判断是否有选中条目
                    var cbs = document.getElementsByName("uid");
                    for (var i = 0; i < cbs.length; i++) {
                        if(cbs[i].checked){
                            //有一个条目选中了
                            flag = true;
                            break;
                        }
                    }

                    if(flag){//有条目被选中
                        //表单提交
                        document.getElementById("form").submit();
                    }

                }
            }

            //1.获取第一个cb
            document.getElementById("firstCb").onclick = function(){
                //2.获取下边列表中所有的cb
                var cbs = document.getElementsByName("uid");
                //3.遍历
                for (var i = 0; i < cbs.length; i++) {
                    //4.设置这些cbs[i]的checked状态 = firstCb.checked
                    cbs[i].checked = this.checked;

                }

            }
        }


    </script>
</head>
<body>
<div class="container">
    <h3 style="text-align: center">用户信息列表</h3>

    <div style="float:left;" >
        <form class="form-inline">
            <div class="form-group">
                <label for="exampleInputName2">姓名</label>
                <input type="text" class="form-control" id="exampleInputName2">
            </div>
            <div class="form-group">
                <label for="exampleInputEmail3">籍贯</label>
                <input type="email" class="form-control" id="exampleInputEmail3" >
            </div>
            <div class="form-group">
                <label for="exampleInputEmail4">E-mail</label>
                <input type="email" class="form-control" id="exampleInputEmail4" >
            </div>
            <button type="submit" class="btn btn-default">查询</button>
        </form>
    </div>

    <div style="float: right;margin: 5px;">
        <a class="btn btn-primary" href="${pageContext.request.contextPath}/add.jsp" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >添加联系人</a>
        <a class="btn btn-primary" href="javascript:void(0);" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  id="delSelected">删除选中</a>
    </div>

    <form action="${pageContext.request.contextPath}/delSelectedServlet" method="post" id="form">
        <table  class="table table-bordered table-hover">
            <tr class="success">
                <th><input type="checkbox" id="firstCb"></th>
                <th>编号</th>
                <th>姓名</th>
                <th>性别</th>
                <th>年龄</th>
                <th>籍贯</th>
                <th>QQ</th>
                <th>邮箱</th>
                <th>操作</th>
            </tr>

            <c:forEach items="${pb.list}" var="user"  varStatus="s" >
                <tr>
                    <td><input type="checkbox" name="uid" value="${user.id}"></td>
                    <td>${s.count}</td>
                    <td>${user.name}</td>
                    <td>${user.gender}</td>
                    <td>${user.age}</td>
                    <td>${user.address}</td>
                    <td>${user.qq}</td>
                    <td>${user.email}</td>
                    <td>
                        <a class="btn btn-default btn-sm" href="${pageContext.request.contextPath}/findUserServlet?id=${user.id}" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >修改</a>&nbsp;
                        <a class="btn btn-default btn-sm" href="javascript:deleteUser(${user.id});" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >删除</a></td>
                </tr>
            </c:forEach>

        </table>
    </form>

    <div>
        <nav aria-label="Page navigation">
            <ul class="pagination">
                <c:if test="${pb.currentPage==1}">
                    <li class="disabled">
                </c:if>

                <c:if test="${pb.currentPage!=1}">
                    <li >
                </c:if>

                <li>
                    <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${pb.currentPage-1}&rows=5" target="_blank" rel="external nofollow"  aria-label="Previous">
                        <span aria-hidden="true">&laquo;</span>
                    </a>
                </li>


                <c:forEach begin="1" end="${pb.totalPage}" var="i">

                    <c:if test="${pb.currentPage==i}">
                        <li class="active">
                            <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${i}&rows=5" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >${i}</a>
                        </li>
                    </c:if>

                    <c:if test="${pb.currentPage!=i}">
                        <li>
                            <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${i}&rows=5" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >${i}</a>
                        </li>
                    </c:if>
                </c:forEach>

                <li>
                    <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${pb.currentPage+1}&rows=5" target="_blank" rel="external nofollow"  aria-label="Next">
                        <span aria-hidden="true">&raquo;</span>
                    </a>
                </li>
                <span style="font-size: 25px;margin-left: 20px">共${pb.totalCount}条记录,共${pb.totalPage}页</span>
            </ul>
        </nav>
    </div>
</div>
</body>
</html>

UserDao

package cn.gtt.dao;

import cn.gtt.pojo.User;

import java.util.List;

/**
 * 用户操作的dao
 */
public interface UserDao {
    /**
     * 查询所有用户信息
     */
    public List<User> findAll();

    /**
     * 登录
     * @param username
     * @param password
     * @return
     */
    User findUserByUsernamePassword(String username,String password);

    /**
     * 添加
     * @param user
     */
    public  void  addUser(User user);

    /**
     * 删除
     * @param id
     */
    void  deleteUser(int id);

    /**
     * 修改
     */
    User findUserById(int id);
   public void updateUser(User user);

    /**
     * 分页
     */
    /**
     * 查询总记录数
     * @return
     */
    int findTotalCount();

    /**
     * 分页查询每页记录
     * @param start
     * @param rows
     * @return
     */
    List<User> findByPage(int start,int rows);

}

UserDaoImpl

package cn.gtt.dao.Impl;

import cn.gtt.dao.UserDao;
import cn.gtt.pojo.User;
import cn.gtt.util.JDBCUtils;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;

import java.util.List;

public class UserDaoImpl implements UserDao {

    private  JdbcTemplate jdbcTemplate=new JdbcTemplate(JDBCUtils.getDataSource());
    /**
     * 查询所有用户信息
     */
    @Override
    public List<User> findAll() {
//        使用JDBC操作数据库
        String sql="select * from user";
        List<User> users = jdbcTemplate.query(sql, new BeanPropertyRowMapper<User>(User.class));
        return users;
    }

    /**
     * 登录
     * @param username
     * @param password
     * @return
     */
    @Override
    public User findUserByUsernamePassword(String username, String password) {
       try {
           String sql="select * from user where username=? and password=?";
           User user = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), username, password);
           return user;
       }catch (Exception e){
            e.printStackTrace();
            return  null;
       }
    }

    /**
     * 添加
     * @param user
     */
    @Override
    public void addUser(User user) {
        String sql="insert into user values(null,?,?,?,?,?,?,null,null)";
        jdbcTemplate.update(sql,user.getName(),user.getGender(),user.getAge(),user.getAddress(),user.getQq(),user.getEmail());
    }

    /**
     * 删除
     */
    @Override
    public void deleteUser(int id) {
        String sql="delete from user where id=?";
        jdbcTemplate.update(sql,id);
    }

    /**
     * 修改
     * @param id
     */
    @Override
    public User findUserById(int id) {
        String sql="select * from  user where id=?";
        User user = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), id);
        return user;
    }

    @Override
    public void updateUser(User user) {
        String sql="update  user set name=?,gender=?,age=?,address=?,qq=?,email=?  where id=?";
        jdbcTemplate.update(sql, user.getName(), user.getGender(), user.getAge(), user.getAddress(), user.getQq(), user.getEmail(), user.getId());
    }

    /**
     * 分页
     */
    /**
     * 查询总记录数
     * @return
     */
    @Override
    public int findTotalCount() {
        String sql="select count(*) from user";
        return jdbcTemplate.queryForObject(sql,Integer.class);
    }

    /**
     * 分页查询每页记录
     * @param start
     * @param rows
     * @return
     */
    @Override
    public List<User> findByPage(int start, int rows) {
        String sql="select * from user limit ?,?";

        return jdbcTemplate.query(sql,new BeanPropertyRowMapper<User>(User.class),start,rows);
    }


}

UserService

package cn.gtt.service;

import cn.gtt.pojo.Page;
import cn.gtt.pojo.User;

import java.util.List;

/**
 * 用户管理的业务接口
 */
public interface UserService {
    /**
     * 查询所有用户信息
     * @return
     */
    public List<User> findAll();

    /**
     * 登录
     * @param user
     * @return
     */
    User login(User user);

    /**
     * 添加
     * @param user
     */
    void addUser(User user);

    /**
     * 删除
     */
    void deleteUser(String id);

    /**
     * 修改
     */
    User  findUserById(String id);
    public void updateUser(User user);

    /**
     * 删除选中
     */
     void delSelecteUser(String[] ids);

    /**
     * 分页查询
     */
    Page<User> findUserByPage(String currentPage, String rows);

}

UserServiceImpl

package cn.gtt.service.Impl;

import cn.gtt.dao.Impl.UserDaoImpl;
import cn.gtt.dao.UserDao;
import cn.gtt.pojo.Page;
import cn.gtt.pojo.User;
import cn.gtt.service.UserService;

import java.util.List;

public class UserServiceImpl implements UserService {

    UserDao userDao=new UserDaoImpl() ;
    /**
     * 查询所有用户信息
     */
    @Override
    public List<User> findAll() {
//        调用userDao完成
        return userDao.findAll();
    }

    /**
     * 登录
     * @param user
     * @return
     */
    @Override
    public User login(User user) {
        return userDao.findUserByUsernamePassword(user.getUsername(),user.getPassword());
    }

    /**
     * 添加
     * @param user
     */
    @Override
    public void addUser(User user) {
        userDao.addUser(user);
    }

    /**
     * 删除
     * @param id
     */
    @Override
    public void deleteUser(String id) {
        userDao.deleteUser(Integer.parseInt(id));
    }

    /**
     * 修改
     * @param id
     */
    @Override
    public User findUserById(String id) {
        return userDao.findUserById(Integer.parseInt(id));
    }

    @Override
    public void updateUser(User user) {
        userDao.updateUser(user);
    }

    /**
     * 删除选中
     * @param ids
     */
    @Override
    public void delSelecteUser(String[] ids) {
        if(ids != null && ids.length > 0){
            //1.遍历数组
            for (String id : ids) {
                //2.调用dao删除
                userDao.deleteUser(Integer.parseInt(id));
            }
        }
    }

    /**
     * 分页查询
     * @return
     */
    @Override
    public Page<User> findUserByPage(String _currentPage, String _rows) {

        int currentPage=Integer.parseInt(_currentPage);
        int rows=Integer.parseInt(_rows);

        if (currentPage<=0){
            currentPage=1;
        }

//        创建空的page对象
        Page<User> pb = new Page<User>();
//        设置参数
        pb.setCurrentPage(currentPage);
        pb.setRows(rows);
//        调用dao查询总记录数
        int totalCount=userDao.findTotalCount();
        pb.setTotalCount(totalCount);
//        调用dao查询list集合
//        计算开始的记录
        int start=(currentPage-1)*rows;
        List<User> list=userDao.findByPage(start,rows);
        pb.setList(list);
//        计算总页码
        int totalPage=totalCount%rows==0?totalCount/rows:(totalCount/rows+1);
        pb.setTotalPage(totalPage);
//        http://localhost:8080/findUserByPageServlet?currentPage=1&rows=5
        System.out.println(pb);
        return pb;
    }


}

FindUserByPageServlet

package cn.gtt.web.servlet;

import cn.gtt.pojo.Page;
import cn.gtt.pojo.User;
import cn.gtt.service.Impl.UserServiceImpl;
import cn.gtt.service.UserService;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

@WebServlet("/findUserByPageServlet")
public class FindUserByPageServlet  extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//        获取参数
//        当前页码
        String currentPage = req.getParameter("currentPage");
//        每页显示的记录数
        String rows = req.getParameter("rows");

        if(currentPage==null||"".equals(currentPage)){
            currentPage="1";
        }
        if(rows==null||"".equals(rows)){
            rows="5";
        }

        

//        调用service查询
        UserService userService=new UserServiceImpl();
        Page<User> pb=userService.findUserByPage(currentPage,rows);

//        将Page存入request
        req.setAttribute("pb",pb);

//        转发到list.jsp
        req.getRequestDispatcher("/list.jsp").forward(req,resp);



    }
}

10 复杂查询

list.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<!-- 网页使用的语言 -->
<html >
<head>
    <!-- 指定字符集 -->
    <meta charset="utf-8">
    <!-- 使用Edge最新的浏览器的渲染方式 -->
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <!-- viewport视口：网页可以根据设置的宽度自动进行适配，在浏览器的内部虚拟一个容器，容器的宽度与设备的宽度相同。
    width: 默认宽度与设备的宽度相同
    initial-scale: 初始的缩放比，为1:1 -->
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <!-- 上述3个meta标签*必须*放在最前面，任何其他内容都*必须*跟随其后！ -->
    <title>用户信息管理系统</title>

    <!-- 1. 导入CSS的全局样式 -->
    <link href="css/bootstrap.min.css" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  rel="stylesheet">
    <!-- 2. jQuery导入，建议使用1.9以上的版本 -->
    <script src="js/jquery-2.1.0.min.js"></script>
    <!-- 3. 导入bootstrap的js文件 -->
    <script src="js/bootstrap.min.js"></script>
    <style type="text/css">
        td, th {
            text-align: center;
        }
    </style>
    <script>
        function  deleteUser(id){
            // 用户安全显示
            if(confirm("您确定要删除么？")){
                // 访问路径
                location.href=" ${pageContext.request.contextPath}/delUserServlet?id=" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" +id;
            }
        }

        window.onload=function (){
            // 给删除选中按钮添加单击事件
            document.getElementById("delSelected").onclick=function (){
                if(confirm("您确定要删除选中条目吗？")){

                    var flag = false;
                    //判断是否有选中条目
                    var cbs = document.getElementsByName("uid");
                    for (var i = 0; i < cbs.length; i++) {
                        if(cbs[i].checked){
                            //有一个条目选中了
                            flag = true;
                            break;
                        }
                    }

                    if(flag){//有条目被选中
                        //表单提交
                        document.getElementById("form").submit();
                    }

                }
            }

            //1.获取第一个cb
            document.getElementById("firstCb").onclick = function(){
                //2.获取下边列表中所有的cb
                var cbs = document.getElementsByName("uid");
                //3.遍历
                for (var i = 0; i < cbs.length; i++) {
                    //4.设置这些cbs[i]的checked状态 = firstCb.checked
                    cbs[i].checked = this.checked;

                }

            }
        }


    </script>
</head>
<body>
<div class="container">
    <h3 style="text-align: center">用户信息列表</h3>

    <div style="float:left;" >
        <form class="form-inline" action="${pageContext.request.contextPath}/findUserByPageServlet" method="post">
            <div class="form-group">
                <label for="exampleInputName2">姓名</label>
                <input type="text" class="form-control" id="exampleInputName2" name="name" value="${condition.name[0]}">
            </div>
            <div class="form-group">
                <label for="exampleInputEmail3">籍贯</label>
                <input type="text" class="form-control" id="exampleInputEmail3" name="address"  value="${condition.address[0]}">
            </div>
            <div class="form-group">
                <label for="exampleInputEmail4">E-mail</label>
                <input type="text" class="form-control" id="exampleInputEmail4" name="email" value="${condition.email[0]}">
            </div>
            <button type="submit" class="btn btn-default">查询</button>
        </form>
    </div>

    <div style="float: right;margin: 5px;">
        <a class="btn btn-primary" href="${pageContext.request.contextPath}/add.jsp" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >添加联系人</a>
        <a class="btn btn-primary" href="javascript:void(0);" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  id="delSelected">删除选中</a>
    </div>

    <form action="${pageContext.request.contextPath}/delSelectedServlet" method="post" id="form">
        <table  class="table table-bordered table-hover">
            <tr class="success">
                <th><input type="checkbox" id="firstCb"></th>
                <th>编号</th>
                <th>姓名</th>
                <th>性别</th>
                <th>年龄</th>
                <th>籍贯</th>
                <th>QQ</th>
                <th>邮箱</th>
                <th>操作</th>
            </tr>

            <c:forEach items="${pb.list}" var="user"  varStatus="s" >
                <tr>
                    <td><input type="checkbox" name="uid" value="${user.id}"></td>
                    <td>${s.count}</td>
                    <td>${user.name}</td>
                    <td>${user.gender}</td>
                    <td>${user.age}</td>
                    <td>${user.address}</td>
                    <td>${user.qq}</td>
                    <td>${user.email}</td>
                    <td>
                        <a class="btn btn-default btn-sm" href="${pageContext.request.contextPath}/findUserServlet?id=${user.id}" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >修改</a>&nbsp;
                        <a class="btn btn-default btn-sm" href="javascript:deleteUser(${user.id});" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >删除</a></td>
                </tr>
            </c:forEach>

        </table>
    </form>

    <div>
        <nav aria-label="Page navigation">
            <ul class="pagination">
                <c:if test="${pb.currentPage==1}">
                    <li class="disabled">
                </c:if>

                <c:if test="${pb.currentPage!=1}">
                    <li >
                </c:if>

                <li>
                    <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${pb.currentPage-1}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}" target="_blank" rel="external nofollow"  aria-label="Previous">
                        <span aria-hidden="true">&laquo;</span>
                    </a>
                </li>


                <c:forEach begin="1" end="${pb.totalPage}" var="i">

                    <c:if test="${pb.currentPage==i}">
                        <li class="active">
                            <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${i}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >${i}</a>
                        </li>
                    </c:if>

                    <c:if test="${pb.currentPage!=i}">
                        <li>
                            <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${i}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}" target="_blank" rel="external nofollow"  target="_blank" rel="external nofollow" >${i}</a>
                        </li>
                    </c:if>
                </c:forEach>

                <li>
                    <a href="${pageContext.request.contextPath}/findUserByPageServlet?currentPage=${pb.currentPage+1}&rows=5&name=${condition.name[0]}&address=${condition.address[0]}&email=${condition.email[0]}" target="_blank" rel="external nofollow"  aria-label="Next">
                        <span aria-hidden="true">&raquo;</span>
                    </a>
                </li>
                <span style="font-size: 25px;margin-left: 20px">共${pb.totalCount}条记录,共${pb.totalPage}页</span>
            </ul>
        </nav>
    </div>
</div>
</body>
</html>

UserDao

package cn.gtt.dao;

import cn.gtt.pojo.User;

import java.util.List;
import java.util.Map;

/**
 * 用户操作的dao
 */
public interface UserDao {
    /**
     * 查询所有用户信息
     */
    public List<User> findAll();

    /**
     * 登录
     * @param username
     * @param password
     * @return
     */
    User findUserByUsernamePassword(String username,String password);

    /**
     * 添加
     * @param user
     */
    public  void  addUser(User user);

    /**
     * 删除
     * @param id
     */
    void  deleteUser(int id);

    /**
     * 修改
     */
    User findUserById(int id);
   public void updateUser(User user);

    /**
     * 分页
     */
    /**
     * 查询总记录数
     * @return
     * @param condition
     */
    int findTotalCount(Map<String, String[]> condition);

    /**
     * 分页查询每页记录
     * @param start
     * @param rows
     * @param condition
     * @return
     */
    List<User> findByPage(int start, int rows, Map<String, String[]> condition);

}

UserDaoImpl

package cn.gtt.dao.Impl;

import cn.gtt.dao.UserDao;
import cn.gtt.pojo.User;
import cn.gtt.util.JDBCUtils;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Set;

public class UserDaoImpl implements UserDao {

    private  JdbcTemplate jdbcTemplate=new JdbcTemplate(JDBCUtils.getDataSource());
    /**
     * 查询所有用户信息
     */
    @Override
    public List<User> findAll() {
//        使用JDBC操作数据库
        String sql="select * from user";
        List<User> users = jdbcTemplate.query(sql, new BeanPropertyRowMapper<User>(User.class));
        return users;
    }

    /**
     * 登录
     * @param username
     * @param password
     * @return
     */
    @Override
    public User findUserByUsernamePassword(String username, String password) {
       try {
           String sql="select * from user where username=? and password=?";
           User user = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), username, password);
           return user;
       }catch (Exception e){
            e.printStackTrace();
            return  null;
       }
    }

    /**
     * 添加
     * @param user
     */
    @Override
    public void addUser(User user) {
        String sql="insert into user values(null,?,?,?,?,?,?,null,null)";
        jdbcTemplate.update(sql,user.getName(),user.getGender(),user.getAge(),user.getAddress(),user.getQq(),user.getEmail());
    }

    /**
     * 删除
     */
    @Override
    public void deleteUser(int id) {
        String sql="delete from user where id=?";
        jdbcTemplate.update(sql,id);
    }

    /**
     * 修改
     * @param id
     */
    @Override
    public User findUserById(int id) {
        String sql="select * from  user where id=?";
        User user = jdbcTemplate.queryForObject(sql, new BeanPropertyRowMapper<User>(User.class), id);
        return user;
    }

    @Override
    public void updateUser(User user) {
        String sql="update  user set name=?,gender=?,age=?,address=?,qq=?,email=?  where id=?";
        jdbcTemplate.update(sql, user.getName(), user.getGender(), user.getAge(), user.getAddress(), user.getQq(), user.getEmail(), user.getId());
    }

    /**
     * 分页
     */
    /**
     * 查询总记录数
     * @return
     * @param condition
     */
    @Override
    public int findTotalCount(Map<String, String[]> condition) {
//        查询总记录数
//        String sql="select count(*) from user";
//        return jdbcTemplate.queryForObject(sql,Integer.class);

//        定义模板初始化sql
        String sql="select count(*) from user where  1=1";
        StringBuffer sb=new StringBuffer(sql);
//        遍历map
        Set<String> keySet = condition.keySet();
//        定义一个参数的集合
        List<Object> params = new ArrayList<>();
        for(String key:keySet){
//            排除分页条件
            if("currentPage".equals(key)||"rows".equals(key)){
                continue;
            }
//            根据键获取value
            String value = condition.get(key)[0];
//            判断value是否有值
            if(value!=null&&!"".equals(value)){
//                有值
                sb.append("   and "+key+" like ?");
//                ?条件的值
                params.add("%"+value+"%");
            }
        }
        System.out.println(sb.toString());
        System.out.println(params);
        return jdbcTemplate.queryForObject(sb.toString(),Integer.class,params.toArray());

    }

    /**
     * 分页查询每页记录
     * @param start
     * @param rows
     * @param condition
     * @return
     */
    @Override
    public List<User> findByPage(int start, int rows, Map<String, String[]> condition) {
        String sql="select * from user where 1=1  ";
        StringBuffer sb=new StringBuffer(sql);
//        遍历map
        Set<String> keySet = condition.keySet();
//        定义一个参数的集合
        List<Object> params = new ArrayList<>();
        for(String key:keySet){
//            排除分页条件
            if("currentPage".equals(key)||"rows".equals(key)){
                continue;
            }
//            根据键获取value
            String value = condition.get(key)[0];
//            判断value是否有值
            if(value!=null&&!"".equals(value)){
//                有值
                sb.append("   and "+key+" like ?");
//                ?条件的值
                params.add("%"+value+"%");
            }
        }

//        添加分页查询
        sb.append("limit ?,?");
        params.add(start);
        params.add(rows);

        return jdbcTemplate.query(sb.toString(),new BeanPropertyRowMapper<User>(User.class),params.toArray());
    }


}

package cn.gtt.service;

import cn.gtt.pojo.Page;
import cn.gtt.pojo.User;

import java.util.List;
import java.util.Map;

/**
 * 用户管理的业务接口
 */
public interface UserService {
    /**
     * 查询所有用户信息
     * @return
     */
    public List<User> findAll();

    /**
     * 登录
     * @param user
     * @return
     */
    User login(User user);

    /**
     * 添加
     * @param user
     */
    void addUser(User user);

    /**
     * 删除
     */
    void deleteUser(String id);

    /**
     * 修改
     */
    User  findUserById(String id);
    public void updateUser(User user);

    /**
     * 删除选中
     */
     void delSelecteUser(String[] ids);

    /**
     * 分页条件查询
     *
     * 条件condition
     */
    Page<User> findUserByPage(String currentPage, String rows, Map<String, String[]> condition);

}

UserServiceImpl

package cn.gtt.service.Impl;

import cn.gtt.dao.Impl.UserDaoImpl;
import cn.gtt.dao.UserDao;
import cn.gtt.pojo.Page;
import cn.gtt.pojo.User;
import cn.gtt.service.UserService;

import java.util.List;
import java.util.Map;

public class UserServiceImpl implements UserService {

    UserDao userDao=new UserDaoImpl() ;
    /**
     * 查询所有用户信息
     */
    @Override
    public List<User> findAll() {
//        调用userDao完成
        return userDao.findAll();
    }

    /**
     * 登录
     * @param user
     * @return
     */
    @Override
    public User login(User user) {
        return userDao.findUserByUsernamePassword(user.getUsername(),user.getPassword());
    }

    /**
     * 添加
     * @param user
     */
    @Override
    public void addUser(User user) {
        userDao.addUser(user);
    }

    /**
     * 删除
     * @param id
     */
    @Override
    public void deleteUser(String id) {
        userDao.deleteUser(Integer.parseInt(id));
    }

    /**
     * 修改
     * @param id
     */
    @Override
    public User findUserById(String id) {
        return userDao.findUserById(Integer.parseInt(id));
    }

    @Override
    public void updateUser(User user) {
        userDao.updateUser(user);
    }

    /**
     * 删除选中
     * @param ids
     */
    @Override
    public void delSelecteUser(String[] ids) {
        if(ids != null && ids.length > 0){
            //1.遍历数组
            for (String id : ids) {
                //2.调用dao删除
                userDao.deleteUser(Integer.parseInt(id));
            }
        }
    }

    /**
     * 分页条件查询
     *
     * 条件condition
     */
    @Override
    public Page<User> findUserByPage(String _currentPage, String _rows, Map<String, String[]> condition) {

        int currentPage=Integer.parseInt(_currentPage);
        int rows=Integer.parseInt(_rows);

        if (currentPage<=0){
            currentPage=1;
        }

//        创建空的page对象
        Page<User> pb = new Page<User>();
//        设置参数
        pb.setCurrentPage(currentPage);
        pb.setRows(rows);
//        调用dao查询总记录数
        int totalCount=userDao.findTotalCount(condition);
        pb.setTotalCount(totalCount);
//        调用dao查询list集合
//        计算开始的记录
        int start=(currentPage-1)*rows;
        List<User> list=userDao.findByPage(start,rows,condition);
        pb.setList(list);
//        计算总页码
        int totalPage=totalCount%rows==0?totalCount/rows:(totalCount/rows+1);
        pb.setTotalPage(totalPage);
//        http://localhost:8080/findUserByPageServlet?currentPage=1&rows=5
        System.out.println(pb);
        return pb;
    }


}

FindUserByPageServlet

package cn.gtt.web.servlet;

import cn.gtt.pojo.Page;
import cn.gtt.pojo.User;
import cn.gtt.service.Impl.UserServiceImpl;
import cn.gtt.service.UserService;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Map;

@WebServlet("/findUserByPageServlet")
public class FindUserByPageServlet  extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("utf-8");

        //        获取参数
//        当前页码
        String currentPage = req.getParameter("currentPage");
//        每页显示的记录数
        String rows = req.getParameter("rows");

        if(currentPage==null||"".equals(currentPage)){
            currentPage="1";
        }
        if(rows==null||"".equals(rows)){
            rows="5";
        }

//        获取条件查询参数
        Map<String, String[]> condition = req.getParameterMap();

//        调用service查询
        UserService userService=new UserServiceImpl();
        Page<User> pb=userService.findUserByPage(currentPage,rows,condition);

//        将Page存入request
        req.setAttribute("pb",pb);
//        将查询条件存起来
        req.setAttribute("condition",condition);
//        转发到list.jsp
        req.getRequestDispatcher("/list.jsp").forward(req,resp);



    }
}

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