JDBC简介
1、注册驱动
2、获取连接对象
3、定义sql
4、获取执行sql的对象
5、执行sql
6、处理结果
7、释放资源

    public static void main(String[] args) throws Exception {
        //Class.forName("com.mysql.cj.jdbc.Driver");
        String url = "jdbc:mysql://127.0.0.1:3306/dbname";
        String username = "root";
        String password = "root";
        Connection conn=DriverManager.getConnection(url,username,password);
        Statement statement = conn.createStatement();
        String sql="update username SET name='zhuhuibin'";
        boolean b = statement.execute(sql);
        System.out.println(b);
        statement.close();
        conn.close();