基本jdbc链接数据库，更改数据

package com.itheima.jdbc;//jdbc

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;

public class JDBCDemo {
    public static void main(String[] args) throws Exception {
        //注册驱动
        Class.forName("com.mysql.jdbc.Driver");

        //获取链接
        String url = "jdbc:mysql://127.0.0.1:3306/db2";
        String username = "root";
        String password = "123456";
        Connection conn = DriverManager.getConnection(url,username,password);

        //定义sql语句
        String sql = "update jdbc set name = '张三' where id = 1 ";

        //获取执行的对象 Statement
        Statement stmt = conn.createStatement();

        //执行sql
        int count = stmt.executeUpdate(sql);

        //处理结果
        System.out.println(count);

        //释放资源
        stmt.close();
        conn.close();


    }
}