mybatis SqlSession事务

最新推荐文章于 2024-11-27 22:55:31 发布

转载最新推荐文章于 2024-11-27 22:55:31 发布 · 2.1k 阅读

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原文链接：http://www.cnblogs.com/suchunping/p/10629832.html

文章标签：

#java

本文介绍了MyBatis框架中默认的SqlSessionFactory实现——DefaultSqlSessionFactory的openSession方法的工作原理。该方法每次获取SqlSession时都会开启一个新的事务，并默认设置为不自动提交。文章通过示例代码展示了如何插入一条记录并手动提交事务以避免在连接关闭时发生回滚。

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mybatis版本：3.4.6。

mybatis默认的SqlSessionFactory是DefaultSqlSessionFactory，它openSession()的源码是：

    public SqlSession openSession() {
        return this.openSessionFromDataSource(this.configuration.getDefaultExecutorType(), (TransactionIsolationLevel)null, false);
    }

    private SqlSession openSessionFromDataSource(ExecutorType execType, TransactionIsolationLevel level, boolean autoCommit) {
        Transaction tx = null;

        DefaultSqlSession var8;
        try {
            Environment environment = this.configuration.getEnvironment();
            TransactionFactory transactionFactory = this.getTransactionFactoryFromEnvironment(environment);
            tx = transactionFactory.newTransaction(environment.getDataSource(), level, autoCommit);
            Executor executor = this.configuration.newExecutor(tx, execType);
            var8 = new DefaultSqlSession(this.configuration, executor, autoCommit);
        } catch (Exception var12) {
            this.closeTransaction(tx);
            throw ExceptionFactory.wrapException("Error opening session.  Cause: " + var12, var12);
        } finally {
            ErrorContext.instance().reset();
        }

        return var8;
    }

可以看到，mybatis默认每次获取session都会开启一个事务，且不自动提交事务。如果更新操作完成后不手动commit，则在连接断开时会将更新操作回滚。

        SqlSession session = MybatisUtil.getSession();
        UserMapper userMapper = session.getMapper(UserMapper.class);
        try{
            UserDomain newUserDomain = new UserDomain();
            newUserDomain.setAge(10);
            newUserDomain.setName("scp2");
            newUserDomain.setSchool("高中");
            userMapper.insert(newUserDomain);
            session.commit();// 如果不commit，连接断开时操作会被回滚
        }
        catch (Exception e){
            System.out.println(e);
        }
        finally {
            if (null != session) {session.close();}
        }