StatelessSession being cast to Session in AbstractEntityPersister (Hibernate)

问题

I'm trying to do a simple save on a StatelessSession. Can someone spot what I'm doing wrong to end up in the Hibernate method that tries to do an invalid cast of StatelessSession to Session. I would appreciate any feedback.

My example code: StatelessSession statelessSession = getSessionFactory().openStatelessSession(); Transaction tx = statelessSession.beginTransaction(); Object ret = null; try { ret = statelessSession.insert(obj); tx.commit(); statelessSession.close();
} catch (Throwable t) { System.out.println("exception: " + t.getMessage()); tx.rollback(); } return (T) ret;

The exception occurs on the .insert(obj) call. Tracing the code lands me in the AbstractEntityPersister class which attempts to cast that StatelessSession to Session in this method:

    private void preInsertInMemoryValueGeneration(Object[] fields, Object object, SessionImplementor session) {
    if ( getEntityMetamodel().hasPreInsertGeneratedValues() ) {
        final InMemoryValueGenerationStrategy[] strategies = getEntityMetamodel().getInMemoryValueGenerationStrategies();
        for ( int i = 0; i < strategies.length; i++ ) {

            if ( strategies[i] != null && strategies[i].getGenerationTiming().includesInsert() ) {
                fields[i] = strategies[i].getValueGenerator().generateValue( (Session) session, object );  // <-- bad cast here
                setPropertyValue( object, i, fields[i] );
            }
        }
    }
}

Here's a stack trace:

java.lang.ClassCastException: org.hibernate.internal.StatelessSessionImpl cannot be cast to org.hibernate.Session
at org.hibernate.persister.entity.AbstractEntityPersister.preInsertInMemoryValueGeneration(AbstractEntityPersister.java:3591)
at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:3568)
at org.hibernate.internal.StatelessSessionImpl.insert(StatelessSessionImpl.java:144)
at org.hibernate.internal.StatelessSessionImpl.insert(StatelessSessionImpl.java:123)
at com.mycompany.somepackage.dao.impl.CommonDAOImpl.persist2(CommonDAOImpl.java:242)
at com.mycompany.somepackage.publisher.ScJournalPublisher.publish(ScJournalPublisher.java:37)
at com.mycompany.somepackage.annotation.callback.CallbackInvoker.invokePublisherCallback(CallbackInvoker.java:92)
at com.mycompany.somepackage.event.listener.DaPostInsertUpdateEventListener.onPostInsert(DaPostInsertUpdateEventListener.java:51)
at org.hibernate.action.internal.EntityInsertAction.postInsert(EntityInsertAction.java:177)
at org.hibernate.action.internal.EntityInsertAction.execute(EntityInsertAction.java:145)
at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:465)
at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:351)
at org.hibernate.event.internal.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:350)
at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:56)
at org.hibernate.internal.SessionImpl.flush(SessionImpl.java:1258)
at org.hibernate.internal.SessionImpl.managedFlush(SessionImpl.java:425)
at org.hibernate.engine.transaction.internal.jdbc.JdbcTransaction.beforeTransactionCommit(JdbcTransaction.java:101)
at org.hibernate.engine.transaction.spi.AbstractTransactionImpl.commit(AbstractTransactionImpl.java:177)
at org.springframework.orm.hibernate4.HibernateTransactionManager.doCommit(HibernateTransactionManager.java:584)
at org.springframework.transaction.support.AbstractPlatformTransactionManager.processCommit(AbstractPlatformTransactionManager.java:757)
at org.springframework.transaction.support.AbstractPlatformTransactionManager.commit(AbstractPlatformTransactionManager.java:726)
at org.springframework.transaction.interceptor.TransactionAspectSupport.commitTransactionAfterReturning(TransactionAspectSupport.java:521)
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:291)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:653)

回答1:

There is already an issue request opened for this! This should be available in Hibernate 5.2.2

https://hibernate.atlassian.net/browse/HHH-11048

getEntityMetamodel().hasPreInsertGeneratedValues() returns true as you must be having something which is generated by hibernate before insert!

Example : Timestamp or Auto generated ids etc.

回答2:

This issue is still in Hibernate last version (5.4.09)

Actual problem is in the entity class, if entity class has some auto generated properties like @CreationTimestamp, hibernate StatelessSession insert/update function will throw this error "java.lang.ClassCastException: org.hibernate.internal.StatelessSessionImpl cannot be cast to org.hibernate.Session"

Eg:

@CreationTimestamp private Date createdDate;

Solution set these kind of properties by manually.

来源：https://stackoverflow.com/questions/38314766/statelesssession-being-cast-to-session-in-abstractentitypersister-hibernate