JDBC概述

由JAVA程序规定一套接口规范，让不同的的数据库商实现
不同的数据库商实现对应的接口、驱动
JDBC是java提供一套用于数据库操作的接口API，java程序员只需要面向这套接口的编程即可

注册驱动 --加载Driver类获取连接–得到Connetion类执行增删改查–发送SQL给 Mysql执行释放资源–关闭相关连接

		Class.forName("com.mysql.cj.jdbc.Driver");//加载驱动，自动注册Driver
        Connection conn = DriverManager.getConnection(URL, USER, PASSWORD);//获取连接
        //3.操作数据库，实现增删改查
        Statement stmt = conn.createStatement();//Statement对象可对表进行增删改查

	//删除
	static public void delete(Connection conn) throws SQLException {
        String s="delete from stu where sno = '01'";
        PreparedStatement ptmt=conn.prepareStatement(s);
        ptmt.execute();
    }
    //添加
    static public void add(Connection conn) throws SQLException {
        Statement stmt = conn.createStatement();
        String sql="insert into stu values('02','秋婷')";
        String sql2="insert into stu values('03','世枫')";
        stmt.executeUpdate(sql);
        stmt.executeUpdate(sql2);
    }
    //更新
    static public void update(Connection conn) throws SQLException {
        Statement stmt = conn.createStatement();
        String sql="update  stu set sno ='01' where sname = '秋婷'";
        String sql2="update  stu set sno ='02' where sname = '世枫'";
       // stmt.executeBatch();
        stmt.executeUpdate(sql);
        stmt.executeUpdate(sql2);
    }
    //查询
    static public void research(Connection conn) throws SQLException {
        Statement stmt = conn.createStatement();
        ResultSet rs = stmt.executeQuery("select * from stu where sno = '01'");
        while(rs.next()){
            System.out.println(rs.getString(1  )+" "+rs.getString(2));
        }
    }
    //输出
    static void info(Connection conn) throws SQLException {
        Statement stmt = conn.createStatement();
        ResultSet rs = stmt.executeQuery("SELECt * FROM stu");//返回查询的结果集--可看作一张表
        //如果有数据，rs.next()返回true
        while(rs.next()){
            System.out.println(rs.getString(1  )+" "+rs.getString(2));
        }
    }