Java Connection.setAutoCommit使用的注意事项

最新推荐文章于 2023-06-30 17:59:04 发布

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最新推荐文章于 2023-06-30 17:59:04 发布

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文章标签： java

原文链接：https://my.oschina.net/u/2308739/blog/684951

本文介绍了一个使用JDBC进行事务管理的示例代码，并指出其中存在的问题。主要问题在于设置了自动提交模式为false后未调用commit或rollback方法。文章还提供了检查Oracle数据库锁定状态的方法及JDBC API关于事务管理的相关说明。

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2019独角兽企业重金招聘Python工程师标准>>>

1  Connection con = null;  
2      try{  
3          con = getConnection();  
4          con.setAutoCommit(false);  
           /* 
5          * update USER set name=’winson’ where id=’000001’; 
            */  
6          con.commit();  
7       }finally{  
8          if(con!=null){  
9              try {  
10                 con.close();  
11             } catch (SQLException e) {  
12                 e.printStackTrace();  
13             }  
           }  
       }

如上是使用commit有问题的代码。是因为setAutoCommit(false)为false了。但是却没有提交或者退回导致的。

附：在oracle上查看锁的方法：select * from v$lock_object或者select * from v$lock.

JDBC的api文档是这样对setAutoCommit方法解释的：

Sets the connection's auto-commit mode to enableAutoCommit.

Newly created Connection objects are in auto-commit mode by default, which means that individual SQL statements are committed automatically when the statement is completed. To be able to group SQL statements into transactions and commit them or roll them back as a unit, auto-commit must be disabled by calling the method setAutoCommit with false as its argument. When auto-commit is disabled, the user must call either the commit or rollback method explicitly to end a transaction.（一定不能大意哦，如果设置成非自动提交，在最后一定要调用commit或者rollback方法）

The commit occurs when the statement completes or the next execute occurs, whichever comes first. In the case of statements returning a ResultSet object, the statement completes when the last row of the result set has been retrieved or the ResultSet object has been closed. In advanced cases, a single statement may return multiple results as well as output parameter values. In this case, the commit may occur when all results and output parameter values have been retrieved, or the commit may occur after each result is retrieved.

另外可以参考官方API关于事务这一块的说明：

https://docs.oracle.com/javase/tutorial/jdbc/basics/transactions.html

转载于:https://my.oschina.net/u/2308739/blog/684951