JAVA解决JDBC的自动提交带来的数据事务出错问题-----JDBC

朴灿烈づ我的快乐病毒、 2024-03-23 19:55 16阅读 0赞

> ###  ###
> 
>     package com.powernode.jdbc;
>     
>     //DROP TABLE IF EXISTS t_act;
>     //CREATE TABLE t_act(actno BIGINT,balance DOUBLE(7,2));//7表示有效数字的个数,2表示小数位的个数
>     //INSERT INTO t_act(actno,balance) VALUES(111,20000);
>     //INSERT INTO t_act(actno,balance) VALUES(222,20000);
>     //COMMIT;
>     //SELECT * FROM t_act;
>     import java.sql.*;
>     import java.util.ResourceBundle;
>     
>     public class JDBCTest04
>     {
>         public static void main(String[] args)
>         {
>             //JDBC的事务都是自动提交的,什么叫自动提交(只要执行任意一条DML语句就会自动提交一次),这是JDBC默认的行为
>             //在业务流程中我们通常是多条SQL语句(DML)同时执行,同时成功,同时失败
>             //JDBC的事务是自动提交机制的,JDBC只要执行容易DML语句就提交一次
>             PreparedStatement preparedStatement = null;
>             Connection connection = null;
>             ResourceBundle resourceBundle = ResourceBundle.getBundle("JDBC");
>             String url = resourceBundle.getString("url");
>             String user = resourceBundle.getString("user");
>             String password = resourceBundle.getString("password");
>             try
>             {
>                 Class.forName(resourceBundle.getString("Driver"));
>                 connection = DriverManager.getConnection(url,user,password);
>                 //将自动提交机制修改为手动提交,开启事务
>                 connection.setAutoCommit(false);
>                 String sql = "update t_act set balance = ? where actno = ?";
>                 preparedStatement = connection.prepareStatement(sql);
>                 preparedStatement.setString(1,"0.0");
>                 preparedStatement.setString(2,"222");
>                 int count = preparedStatement.executeUpdate();
>                 //终止程序的空指针异常
>     //            String s = null;
>     //            s.toString();
>     
>                 preparedStatement.setString(1,"10000.0");
>                 preparedStatement.setString(2,"222");
>                 count = preparedStatement.executeUpdate() + count;
>                 System.out.println(count == 2 ? "转账成功" : "转账失败");
>                 //能走到这就是没有异常,手动提交数据
>                 connection.commit();
>             }
>             catch(Exception e)
>             {
>                 if (connection != null)
>                 {
>                     try
>                     {
>                         //回滚事务
>                         connection.rollback();
>                     } catch (SQLException ex)
>                     {
>                         throw new RuntimeException(ex);
>                     }
>                 }
>                 e.printStackTrace();
>             }
>             finally
>             {
>                 if (preparedStatement != null)
>                 {
>                     try
>                     {
>                         preparedStatement.close();
>                     }
>                     catch (SQLException e)
>                     {
>                         throw new RuntimeException(e);
>                     }
>                 }
>                 if (connection != null)
>                 {
>                     try
>                     {
>                         connection.close();
>                     }
>                     catch (SQLException e)
>                     {
>                         throw new RuntimeException(e);
>                     }
>                 }
>             }
>         }
>     }
> 
> package com.powernode.jdbc;  
>   
> //DROP TABLE IF EXISTS t\_act;  
> //CREATE TABLE t\_act(actno BIGINT,balance DOUBLE(7,2));//7表示有效数字的个数,2表示小数位的个数  
> //INSERT INTO t\_act(actno,balance) VALUES(111,20000);  
> //INSERT INTO t\_act(actno,balance) VALUES(222,20000);  
> //COMMIT;  
> //SELECT \* FROM t\_act;  
> import java.sql.\*;  
> import java.util.ResourceBundle;  
>   
> public class JDBCTest04  
> \{  
> public static void main(String\[\] args)  
> \{  
> //JDBC的事务都是自动提交的,什么叫自动提交(只要执行任意一条DML语句就会自动提交一次),这是JDBC默认的行为  
> //在业务流程中我们通常是多条SQL语句(DML)同时执行,同时成功,同时失败  
> //JDBC的事务是自动提交机制的,JDBC只要执行容易DML语句就提交一次  
> PreparedStatement preparedStatement = null;  
> Connection connection = null;  
> ResourceBundle resourceBundle = ResourceBundle.getBundle("JDBC");  
> String url = resourceBundle.getString("url");  
> String user = resourceBundle.getString("user");  
> String password = resourceBundle.getString("password");  
> try  
> \{  
> Class.forName(resourceBundle.getString("Driver"));  
> connection = DriverManager.getConnection(url,user,password);  
> //将自动提交机制修改为手动提交,开启事务  
> connection.setAutoCommit(false);  
> String sql = "update t\_act set balance = ? where actno = ?";  
> preparedStatement = connection.prepareStatement(sql);  
> preparedStatement.setString(1,"0.0");  
> preparedStatement.setString(2,"222");  
> int count = preparedStatement.executeUpdate();  
> //终止程序的空指针异常  
> // String s = null;  
> // s.toString();  
>   
> preparedStatement.setString(1,"10000.0");  
> preparedStatement.setString(2,"222");  
> count = preparedStatement.executeUpdate() + count;  
> System.out.println(count == 2 ? "转账成功" : "转账失败");  
> //能走到这就是没有异常,手动提交数据  
> connection.commit();  
> \}  
> catch(Exception e)  
> \{  
> if (connection != null)  
> \{  
> try  
> \{  
> //回滚事务  
> connection.rollback();  
> \} catch (SQLException ex)  
> \{  
> throw new RuntimeException(ex);  
> \}  
> \}  
> e.printStackTrace();  
> \}  
> finally  
> \{  
> if (preparedStatement != null)  
> \{  
> try  
> \{  
> preparedStatement.close();  
> \}  
> catch (SQLException e)  
> \{  
> throw new RuntimeException(e);  
> \}  
> \}  
> if (connection != null)  
> \{  
> try  
> \{  
> connection.close();  
> \}  
> catch (SQLException e)  
> \{  
> throw new RuntimeException(e);  
> \}  
> \}  
> \}  
> \}  
> \}