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Spring Boot 整合 WebSocket 之 注解驱动

JSR 356, Java API for WebSocket(本篇文章记录注解实现websocket) 

websocket支持两种不同的编程方式：

1.基于注解驱动，使用带注释的POJO，可以与WebSocket生命周期事件进行交互

2.基于接口驱动，可以实现Endpoint与生命周期事件交互的接口和方法

官网参考资料：

ORACLE JAVA:https://www.oracle.com/technetwork/articles/java/jsr356-1937161.html

J2EE 7:https://docs.oracle.com/javaee/7/tutorial/websocket.htm

1.maven依赖

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-websocket</artifactId>
</dependency>

2.ServerEndpointExporter配置

/**
 * 外部tomcat由容器自己提供
 * @author Administrator
 *
 */
@Configuration
public class ServerEndpointExporterConfigure {

    @Bean
    public ServerEndpointExporter serverEndpointExporter() {
        return new ServerEndpointExporter();
    }
}

3.创建WebSocket请求的端点

import java.io.IOException;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.AtomicInteger;
import javax.servlet.http.HttpSession;
import javax.websocket.CloseReason;
import javax.websocket.EndpointConfig;
import javax.websocket.OnClose;
import javax.websocket.OnError;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;
import org.springframework.stereotype.Component;
import lombok.extern.slf4j.Slf4j;

@Slf4j
@Component
@ServerEndpoint(value="/websocket/{sid}",configurator=HttpSessionConfigurator.class)
public class ServerEndpointConfigure {

	//设定原子整型,用来记录当前在线连接数
    private AtomicInteger onlineCount = new AtomicInteger(0);
    //concurrent包的线程安全Set，用来存放每个客户端对应的MyWebSocket对象。
//    private static CopyOnWriteArraySet<ServerEndpointConfigure> webSocketSet = new CopyOnWriteArraySet<ServerEndpointConfigure>();
    //若要实现服务端与指定客户端通信的话，可以使用Map来存放，其中Key可以为用户标识
//    public static ConcurrentHashMap<Session,Object> webSocketMap = new ConcurrentHashMap<Session,Object>();
    
    //绑定HttpSession与session
    public static ConcurrentHashMap<String,Session> bizSession = new ConcurrentHashMap<String,Session>();
	//与某个客户端的连接会话，需要通过它来给客户端发送数据
    private Session session;
 
    /**
     * <p>连接建立成功调用的方法</p>
     * @throws IOException 
     **/
    @OnOpen
    public void onOpen(Session session,EndpointConfig config,@PathParam("sid") String sid) throws IOException {
        this.session = session;
        HttpSession httpSession = (HttpSession) config.getUserProperties().get(HttpSession.class.getName());
        log.info("httpSessionId:{},websocketSessionId:{},sid:{}----",httpSession.getId(),session.getId(),sid);        
        bizSession.put(httpSession.getId(), session);//建立关联
        addOnlineCount();//在线数加1
        log.info("有新连接加入！当前在线人数为" + getOnlineCount());
        try {
        	 sendMessage("["+httpSession.getId()+"]连接成功",session);
        	 //设定模拟线程
        	 new Thread(new Heartbeat(session)).start();
        } catch (IOException e) {
            log.error("websocket IO异常");
        }
    }
    
    /**
     * <p>连接关闭调用的方法</p>
     */
    @OnClose
    public void onClose(Session closeSession,CloseReason reason) {
    	log.info(reason.toString());
    	for(String key:bizSession.keySet()){
    		Session session = bizSession.get(key);
    		if(session.equals(closeSession)){
    			bizSession.remove(key);
    		}
    	}   	
        subOnlineCount();           //在线数减1
        log.info("有一连接关闭！当前在线人数为" + getOnlineCount());
    }

    /**
     * <p>收到客户端消息后调用的方法</p>
     *
     * @param message 客户端发送过来的消息*/
    @OnMessage
    public void onMessage(String message, Session mySession) {
    	log.info("来自客户端的消息:" + message);
    	try {
			sendMessage(message, mySession);
		} catch (IOException e) {
			e.printStackTrace();
		}
    }
 
	/**
	 * 
	 * @param session
	 * @param error
	 */
    @OnError
    public void onError(Session session, Throwable error) {
        log.error("发生错误");
        for(String key:bizSession.keySet()){
    		Session sessionc = bizSession.get(key);
    		if(session.equals(sessionc)){
    			bizSession.remove(key);
    		}
    	} 
        error.printStackTrace();
    }
       
 
    public void sendMessage(String message,Session session) throws IOException {   	
    	try {
			if(session.isOpen()){//该session如果已被删除，则不执行发送请求，防止报错
				session.getBasicRemote().sendText(message);
			}
		} catch (IOException e) {
			e.printStackTrace();
		}   	
    }

    
    public int getOnlineCount() {//获取当前值
		return onlineCount.get();   	
    }
    
    public int addOnlineCount() {//加1
    	return onlineCount.getAndIncrement();
    }
   
    public int subOnlineCount() {//减1
    	return onlineCount.getAndDecrement();
    }
}

这里configurator指定了端点配置器类，端点类可以使用握手请求对象来访问初始HTTP请求的详细信息，获取HttpSession对象

，不需要的话可以去掉

HttpSessionConfigurator 类

public class HttpSessionConfigurator extends Configurator {

	@Override
	public void modifyHandshake(ServerEndpointConfig sec, HandshakeRequest request, HandshakeResponse response) {
		HttpSession httpSession = (HttpSession) request.getHttpSession();
		sec.getUserProperties().put(HttpSession.class.getName(), httpSession);
	}
	
}

 以下配置是避免获取httpsession出现空指针的情况，事先带上

@Component
public class RequestListener implements ServletRequestListener {

	@Override
	public void requestDestroyed(ServletRequestEvent sre) {
		// TODO Auto-generated method stub
		ServletRequestListener.super.requestDestroyed(sre);
	}

	@Override
	public void requestInitialized(ServletRequestEvent sre) {
		 //将所有request请求都携带上httpSession
		HttpServletRequest req = (HttpServletRequest) sre.getServletRequest();
		req.getSession();
//        ((HttpServletRequest) sre.getServletRequest()).getSession();
	}
	
	
}

 放入监听

@SpringBootApplication
public class SpringbootWebsocketApplication {

    public static void main(String[] args) {
        SpringApplication.run(SpringbootWebsocketApplication.class, args);
    }
    
    @Autowired
    private RequestListener requestListener;
  
    @Bean
    public ServletListenerRegistrationBean<RequestListener> servletListenerRegistrationBean() {
         ServletListenerRegistrationBean<RequestListener> servletListenerRegistrationBean = new ServletListenerRegistrationBean<>();
         servletListenerRegistrationBean.setListener(requestListener);
         return servletListenerRegistrationBean;
    }

}

Heartbeat类

public class Heartbeat implements Runnable {
	
	private Logger log = LoggerFactory.getLogger(Heartbeat.class);
	
	private Session session;
	
	public Heartbeat(Session session) {
		super();
		this.session = session;
	}

	
	public Heartbeat() {
		super();
	}


	@Override
	public void run() {
		log.info("服务端开启发送心跳模式");
		int i = 0;
		while(session.isOpen()) {
			try {
				String uuid = String.format("%04d", i++)+":the websoket heart is exist 3s";
				log.info(uuid);
				session.getBasicRemote().sendText(uuid);
				Thread.sleep(1000*3);
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
	}

}

3.Controller控制层

@Controller
@Slf4j
public class DemoController {
	
    @GetMapping("demo")
    @ResponseBody
    public String demo() {
        return "this is a demo~";
    }
    
    @RequestMapping("/")
    public String index(Model model,HttpServletRequest request) {
    	HttpSession session = request.getSession();
    	model.addAttribute("sid", session.getId());
    	log.info("初始化websocket页面~");
		return "index";   	
    }
    
}

4.html

<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%>
<%
    String path = request.getContextPath();
    String basepath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";

%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>websocket页面</title>
</head>
<script type="text/javascript" src="https://cdn.bootcss.com/jquery/3.3.1/jquery.min.js"></script>
<script type="text/javascript">
	var websocket = null;
	socket();//初始化
	function socket(){
		//判断当前浏览器是否支持WebSocket  
		if ('WebSocket' in window) {  
		    websocket = new WebSocket("ws://localhost:8080/websocket/${sid}");  
		}  
		else {  
		    alert('Not support websocket');
		}
		
		//连接发生错误的回调方法
		websocket.onerror = function(){
			setMessage("连接发生错误");
		};
		
		//连接成功建立的回调方法
		websocket.onopen = function(event){
			console.log("连接成功建立");
		}
		
		//接收到消息的回调方法
		websocket.onmessage = function(event){
			setMessage(event.data);
		}
		
		//连接关闭的回调方法
		websocket.onclose = function(code,reason){
			setMessage("连接关闭");
		}
		
		//监听窗口关闭事件，当窗口关闭时，主动去关闭websocket连接，防止连接还没断开就关闭窗口，server端会抛异常。
		window.onbeforeunload = function(){
		    websocket.close();
		}
	}
	
	//将消息显示在网页上
	function setMessage(message){
	    $('#message').append(message+"\n");
	}
	
	function sendMessage(){
	   var msg = $('#content').val();
	   websocket.send(msg);
	}
	
</script>
<body>
	<div>
		<table>
			<tr>
				<td><input type="button" value="发送消息" onclick="sendMessage()"/></td>
				<td>websocket服务端返回信息:</td>
			</tr>
			<tr>
				<td>
					<textarea rows="50" cols="100" id="content"></textarea>
				</td>
				<td>
					<textarea rows="50" cols="100" readonly="readonly" id="message"></textarea>
				</td>
			</tr>
		</table>
	</div>
</body>
</html>

5.启动最终效果