一天搞定JDBC02：开启事务

package JDBCTest;

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

public class JDBCDemo3 {
    
    public static void main(String[] args) throws Exception{
    
        //1.注册驱动
        Class.forName("com.mysql.jdbc.Driver");

        //2.获取连接
        String url="jdbc:mysql://127.0.0.1:3306/test?useSSL=false";
        String username="root";
        String password="lyt2529165097";
        Connection conn = DriverManager.getConnection(url, username, password);

        //3.定义一个sql语句
        String sql="UPDATE emp set age =age+10 WHERE age>20";
        String sql1=" UPDATE emp set age =age+10 WHERE age<20 ";

        //4.获取执行sql的对象 statement
        Statement stmt = conn.createStatement();//获取执行sql的对象


        try {
    
            //开启事务
            conn.setAutoCommit(false);//true为自动提交事务,false为手动提交事务,即为开启事务
            //5.执行sql
            int count = stmt.executeUpdate(sql);
            //6.处理结果
            System.out.println(count);
            int count1 = stmt.executeUpdate(sql);
            System.out.println(count1);
            //提交事务
            conn.commit();
        } catch (Exception throwables) {
    
            //回滚事务
            conn.rollback();
            throwables.printStackTrace();
        }

        //7.释放资源
        stmt.close();
        conn.close();

        //executeUpdate(sql)：执行DML、DDL语句 返回值 DML语句影响的行数
        //ResultSet executeQuery(sql)：执行DQL语句  ResultSet结果集对象

    }
}