Hibernate5.2.x“事务已经激活”的怪异行为

从Hibernate4.x迁移到Hibernate5的最新版本时,我遇到了一个事务管理方面的问题。

Session.beginTransaction . 下面是一个重现问题的示例(该场景不使用Spring或任何其他容器管理的事务管理):

transactionManager.begin();
saveOrUpdate(entity1);
saveOrUpdate(entity2);
...
transactionManager.commit();

private void saveOrUpdate(SomeEntity entity) {
    try (Session session = sessionFactory.openSession()) {
        session.setFlushMode(FlushMode.AUTO);
        session.beginTransaction();   // throws IllegalStateException "Transaction already active"
        try {
            session.saveOrUpdate(entity);
            session.getTransaction().commit();
        } catch (Exception ex) {
            session.getTransaction().rollback();
            throw RuntimeException(ex);
        }
    }
}

这导致了 IllegalStateException 与消息一起抛出 "Transaction already active" . 这种行为似乎是在Hibernate5.2.0中引入的( this is the commit ). 以前,Hibernate只是忽略了物理事务本身的开头,因为它知道存在封闭事务 :它只是创建一个包装器 JtaTransaction isInitiator 设置为false。

此异常被抛出 org.hibernate.engine.transaction.internal.TransactionImpl ,特别是 begin() 方法:

@Override
public void begin() {
    if ( !session.isOpen() ) {
        throw new IllegalStateException( "Cannot begin Transaction on closed Session/EntityManager" );
    }

    if ( transactionDriverControl == null ) {
        transactionDriverControl = transactionCoordinator.getTransactionDriverControl();
    }

    // per-JPA
    if ( isActive() ) {   // *** This is the problematic part *** //
        throw new IllegalStateException( "Transaction already active" );
    }

    LOG.debug( "begin" );

    this.transactionDriverControl.begin();
}

这也与事实相矛盾 user manual

// Note: depending on the JtaPlatform used and some optional settings,
// the underlying transactions here will be controlled through either
// the JTA TransactionManager or UserTransaction

Session session = sessionFactory.openSession();
try {
    // Assuming a JTA transaction is not already active,
    // this call the TM/UT begin method.  If a JTA
    // transaction is already active, we remember that
    // the Transaction associated with the Session did
    // not "initiate" the JTA transaction and will later
    // nop-op the commit and rollback calls...
    session.getTransaction().begin();