// SQL_Server:

String driver  =   " com.microsoft.jdbc.sqlserver.SQLServerDriver " ;
String url  =   " jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=test " ;
String user  =   " sa " ;
String password  =   "" ;


// Oracle:

String driver  =   " oracle.jdbc.driver.OracleDriver " ;
String url  =   " jdbc:oracle:thin:@localhost:1521:wanchao " ;
String user  =   " scott " ;
String password  =   " tiger " ;


// mysql
String driver = " com.mysql.jdbc.Driver " ;
String url = " jdbc:mysql://localhost:3306/chinabank?useUnicode=true&characterEncoding=GBK " ;
String user = " root " ;
String passeord = " root " ;

Class.forName(driver);
con  =  DriverManager.getConnection(url,user,password);