package cn.itcast.jdbc.util;

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

public class JDBCDemo7 {
    public static void main(String[] args) {
        Connection conn=null;
        PreparedStatement pstmt1=null;
        PreparedStatement pstmt2=null;
        ResultSet rs=null;
        //注册驱动 获取数据库连接对象
        try {
            conn = JDBCUtils.getConnection();
            //开启事务
            conn.setAutoCommit(false);
            //定义sql语句
            String sql1="update account set balance=balance-? where id=?";
            String sql2="update account set balance=balance+? where id=?";
            //获取执行sql对象
            pstmt1 = conn.prepareStatement(sql1);
            pstmt2 = conn.prepareStatement(sql2);
            //给sql语句赋值
            pstmt1.setDouble(1,50);
            pstmt1.setInt(2,1);
            pstmt2.setDouble(1,50);
            pstmt2.setInt(2,2);
            //增加bug
            int a=3/0;
            //执行sql语句
            pstmt1.executeUpdate();
            pstmt2.executeUpdate();
            //若程序没问题则提交事务
            conn.commit();
        } catch (SQLException e) {
            e.printStackTrace();
            //若程序有问题则回滚事务
            try {
                conn.rollback();
            } catch (SQLException ex) {
                ex.printStackTrace();
            }
        }finally {
            JDBCUtils.close(pstmt1,conn);
            JDBCUtils.close(pstmt2,null);
        }
    }
}