Java和MySQL的运用

package com.zhongruan.demo;

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

public class Demo1 {
    public static void main(String[] args) throws ClassNotFoundException, SQLException {
        //  1.导入jar包		mysql-connector-java-5.1.37-bin.jar
        //​	2.注册驱动
        Class.forName("com.mysql.jdbc.Driver");//加载这个类
        //​	3.获取数据库连接对象	Connection
        Connection conn = DriverManager.getConnection("jdbc:mysql:///db4","root", "root");
        //​	4.定义sql
        String sql = "update student set age = 35 where id = 1 ";
        //​	5.获取执行sql语句的对象	Statement
        Statement stat = conn.createStatement();
        //​	6.执行sql，接受返回结果
        int count = stat.executeUpdate(sql);
        //​	7.处理结果
        System.out.println(count);
        //​	8.释放资源
        stat.close();
        conn.close();
    }
}

package com.zhongruan.demo;

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

public class Demo2 {
    public static void main(String[] args) {
        Connection conn = null;
        Statement stat = null;
        //  1.导入jar包		mysql-connector-java-5.1.37-bin.jar
        try {
            //​ 2.注册驱动
            Class.forName("com.mysql.jdbc.Driver");
            //​ 3.获取Connection对象
            conn = DriverManager.getConnection("jdbc:mysql:///db4", "root", "root");
            // 4.定义sql
            String sql = "INSERT INTO student VALUES(3,'han', 18, 80.00,NULL,NULL)";
            //​ 5.获取执行sql语句的对象	Statement
            stat = conn.createStatement();
            // 6.执行sql，接受返回结果
            int count = stat.executeUpdate(sql);
            //​ 7.处理结果
            System.out.println(count);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }finally {
            //​ 8.释放资源
            if(stat != null) {
                try {
                    stat.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if (conn != null) {
                try {
                    conn.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }

        }

    }
}