Java操作数据库(行级锁,for update)

//sql指令
            String sql = "select * from  t_shuihuo where id < ? for update ";

package com.luosf.jdbc;
 
import com.luosf.jdbc.utils.JdbcUtil;
 
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
 
/**
 * JDBC中锁的使用
 * for updata
 */
public class JdbcLock {
    public static void main(String[] args) {
        Connection conn = null;
        PreparedStatement stat = null;
        ResultSet res = null;
        try {
            //创建驱动
 
            //获取数据库对象
             conn = JdbcUtil.getConnection();
 
            //sql指令
            String sql = "select * from  t_shuihuo where id < ? for update ";
 
            conn.setAutoCommit(false);//开启事务
 
            //3,sql语句进行编译
            stat = conn.prepareStatement(sql);
 
            //给占位符填充值
            //JDBC下标从1开始的
            stat.setInt(1,16); //1,代表第一个问号
 
            Thread.sleep(1000*10); //模拟访问时间
 
            //4,执行sql
            res = stat.executeQuery();
 
            //5,处理查询结果集
            while (res.next()){
                int id = res.getInt("id");
                String name = res.getString("name");
                String nickname = res.getString("nickname");
                System.out.println("id :"+ id + "  name :" +name + "  昵称 ："+nickname);
            }
            conn.commit();//提交事务
        } catch (SQLException throwables) {
            try {
                if (conn != null){
                    conn.rollback(); //回滚事务
                }
 
            } catch (SQLException e) {
                e.printStackTrace();
            }
            throwables.printStackTrace();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally{
            //释放资源
            JdbcUtil.close(conn,stat,res);
        }
    }
}

package com.luosf.jdbc;
 
import com.luosf.jdbc.utils.JdbcUtil;
 
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;
 
/**
 * 检测锁
 */
public class JdbcLockTest {
    public static void main(String[] args) {
        Connection conn = null;
        PreparedStatement stat = null;
 
        try {
            //获取驱动
 
            //获取数据库链接对象
            conn = JdbcUtil.getConnection();
 
            //开启事务
            conn.setAutoCommit(false);
 
            //锁开始后进行修改数据
            String sql = "update t_shuihuo set name = '小罗' where id  = ?  ";
            stat = conn.prepareStatement(sql);
 
            stat.setInt(1,10); //1,代表第一个问号
 
            int cunt = stat.executeUpdate();
            System.out.println("更新了"+cunt+"条数据");
 
            conn.commit();//提交事务
        } catch (SQLException throwables) {
            try {
                if (conn != null){
                    conn.rollback();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
            throwables.printStackTrace();
        } finally {
            //释放资源
           JdbcUtil.close(conn,stat,null);
        }
    }
}