【后端】JDBC事务提交与回滚小练习

JDBC事务提交与回滚小练习

需求：zhangsan给lisi转账500元，要求利用事务提交与回滚来规避数据丢失风险
备注：数据库，工具类和配置文件在我的这篇文章内

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class jdbcdemo9 {

    public static void main(String[] args) {
        PreparedStatement preparedStatement1 = null;
        PreparedStatement preparedStatement2 = null;
        Connection connections = null;
        //数据库连接
        try {
            connections = JDBC_utils.getConnections();
            //开启事务 false开启
            connections.setAutoCommit(false);
            //第二步 定义sql语句
            String sql01 = "update  account set balance = balance - ? where id = ?";
            String sql02 = "update  account set balance = balance + ? where id = ?";
            //创建执行sql对象
            preparedStatement1 = connections.prepareStatement(sql01);
            preparedStatement2 = connections.prepareStatement(sql02);
            //set 占位符值
            preparedStatement1.setDouble(1, 500);
            preparedStatement1.setInt(2, 1);
            preparedStatement2.setDouble(1, 500);
            preparedStatement2.setInt(2, 2);
            //执行sql
            preparedStatement1.executeUpdate();
            preparedStatement2.executeUpdate();
            //手动制造异常！数据回滚 全部失效
            int i = 2 / 0;
            //提交事务
            connections.commit();


        } catch (SQLException e) {
            //回滚
            if (connections != null) {
                try {
                    connections.rollback();
                } catch (SQLException ex) {
                    ex.printStackTrace();
                }
            }
            e.printStackTrace();

        } finally {
            JDBC_utils.Close(preparedStatement1, connections);
            JDBC_utils.Close(preparedStatement2, connections);
        }

    }
}