复习（DBUtils 写法,封装工具类）

public class DBUtils{

public static Connection getConnection(){

Connection con=null;

try{

Class.forName("com.mysql..........")

con=DriverManger.getconnection(url:.........,user:..,password:.......)

catch{......}

}

return con;

}

public static void closeAll(Connection con ,Preparedstatic pst, Resultset rs ){

if( rs!=0){

close().rs

}

.....

}

}