Question

如果事务运行时间过长，我会尝试停止/回滚事务。但是通过配置spring的事务管理器的timeout属性似乎不起作用。我的环境：

spring 2.5.6 + JPA + hibernate 3.2.6
oracle 10g
jdk 1.6.0_17

由于spring有助于管理我的交易，因此配置如下：

<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
    <property name="entityManagerFactory" ref="entityManagerFactory" />
    <property name="dataSource" ref="dataSource" />
</bean>

<!-- the transactional advice (what 'happens'; see the <aop:advisor/> bean 
    below) -->
<tx:advice id="defaultTxAdvice" transaction-manager="transactionManager">
    <tx:attributes>
        <!-- Keep SequenceService in a isolation transaction -->
        <tx:method name="get*" read-only="true" />
        <!-- By default, A runtime exception will rollback transaction. -->
        <tx:method name="*" timeout="10" rollback-for="ApplicationException" />
    </tx:attributes>
</tx:advice>

我有一个TicketService，它会将一些记录插入数据库，只需让它再睡15秒。

public class DefaultTicketService implements TicketService{
    public void sell() {
        // checking and insert some records to underlying database
        ....
        // sleep to reach the transaction deadline
        try {Thread.sleep(15 * 1000);} catch(Exception e){}
    }
}

此外，我修改了spring的 org.springframework.orm.jpa.JpaTransactionManager 以输出更多调试信息。

protected void doBegin(Object transaction, TransactionDefinition definition) {
    ... ...        
    // Register transaction timeout.
    int timeout = determineTimeout(definition);
    if (timeout != TransactionDefinition.TIMEOUT_DEFAULT) {
        if (logger.isDebugEnabled()) {
            logger.debug("****setTimeoutinSeconds(" + timeout
                    + " seconds) to EntityManager(" + txObject.getEntityManagerHolder()
                    + "), the transaction begin time:"
                    + new Date(System.currentTimeMillis()));
        }
        txObject.getEntityManagerHolder().setTimeoutInSeconds(timeout);
    }
    ... ... 
}

protected void doCommit(DefaultTransactionStatus status) {
    JpaTransactionObject txObject = (JpaTransactionObject) status.getTransaction();
    if (status.isDebug()) {
        logger.debug("Committing JPA transaction on EntityManager ["
                + txObject.getEntityManagerHolder().getEntityManager() + "]");
    }
    try {
        if (status.isDebug()) {
            logger.debug("The deadline of entityManager("
                    + txObject.getEntityManagerHolder().getEntityManager() + "):"
                    + txObject.getEntityManagerHolder().getDeadline() + ", and current time:"
                    + new Date(System.currentTimeMillis()));
        }
        EntityTransaction tx = txObject.getEntityManagerHolder().getEntityManager()
                .getTransaction();
        tx.commit();
    ... ...
}

完成测试后，结果超出我的预期，交易最后提交。以下是测试的输出：

[JpaTransactionManager] Opened new EntityManager [org.hibernate.ejb.EntityManagerImpl@350225] for JPA transaction
[JpaTransactionManager] ****[Begin]timeout:10 seconds,The deadline of entityManager(org.hibernate.ejb.EntityManagerImpl@350225):null, and current time:Tue Sep 06 15:05:42 CST 2011
[JpaTransactionManager] Exposing JPA transaction as JDBC transaction [SimpleConnectionHandle: com.mchange.v2.c3p0.impl.NewProxyConnection@1eb41d6]
[JpaTransactionManager] Found thread-bound EntityManager [org.hibernate.ejb.EntityManagerImpl@350225] for JPA transaction
... ...
[JpaTransactionManager] Initiating transaction commit
[JpaTransactionManager] Committing JPA transaction on EntityManager [org.hibernate.ejb.EntityManagerImpl@350225]
[JpaTransactionManager] ****[Commit]The deadline of entityManager(org.hibernate.ejb.EntityManagerImpl@350225):Tue Sep 06 15:05:52 CST 2011, and current time:Tue Sep 06 15:05:58 CST 2011
[JpaTransactionManager] Closing JPA EntityManager [org.hibernate.ejb.EntityManagerImpl@350225] after transaction
[EntityManagerFactoryUtils] Closing JPA EntityManager

从调试信息来看，显然当前时间已超过截止日期，那么为什么spring不会回滚事务？在我的理解中，如果我设置超时，例如10秒，Spring将在启动新事务时启动Timer，如果计时器达到时间限制，它将回滚事务。你能告诉我为什么???

更新＆GT;＆GT;

当经历JavaEE7的教程时，发现似乎JPA2.1提供了对锁超时的支持（一般事务超时是由获取锁的超时引起的。）

http://docs.oracle.com/javaee/7/tutorial/doc/persistence-locking002.htm

42.2.2.1悲观锁定超时

Answer 1

我找到了解决方案JpaTransactionManager does not support transaction timeouts

Answer 2

经过一番研究，我发现问题在于TimerTask线程没有使用通常启动和提交事务的弹簧代理。从理论上讲，你可以手动将支持编码到你的TimerTask中以使用代理，但这对我来说似乎很麻烦。

Spring拥有自己的调度框架，您可以使用它而不是TimerTask来执行runnables，并且不需要太多的代码更改来代替使用。

这是文档：

http://static.springsource.org/spring/docs/3.0.5.RELEASE/reference/scheduling.html

spring transaction timeout不起作用

2 个答案: