Question

在我的java应用程序中，我使用Hibernate Envers来监听持久性事件。我的听众课看起来像这样。

@Component
public class DataCreationListener extends EnversPostInsertEventListenerImpl {

    private static final long serialVersionUID = 1L;

    @Autowired
    DataService DataService;

    public DataCreationListener() {
        super(null);
    }

    @Override
    public void onPostInsert(PostInsertEvent event) {

        if (event.getEntity() instanceof DataDAO) {
            Data Data = DataService.fromDao((DataDAO) event.getEntity());
            // other stuff
        }
    }

}

在fromDAO方法中，我将DAO（实体类型）对象转换为api类型对象。这是fromDAO方法

@Override
    public Data fromDao(DataDAO data) {
        if (data == null) {
            return null;
        }
        Data api = new Data();
        api.setId(data.getIdUser());
        api.setAddress(data.getAddress());
        api.setCity(data.getCity());
        api.setCountry(getCountryFromId(data.getId()));

        return api;
    }

执行getCountryFromId(data.getId())

时出错

此方法涉及发生错误的Spring Data JPA存储库调用。存储库调用看起来像这样

repository.findByCountry_Id(dataId);

在调试时，我看到dataId具有非null值，repository非null，查询应该给出有效结果。但不知何故发生了这种错误

04:15:10.504 [http-nio-8080-exec-2] ERROR org.hibernate.AssertionFailure - HHH000099: an assertion failure occured (this may indicate a bug in Hibernate, but is more likely due to unsafe use of the session): org.hibernate.AssertionFailure: null id in my.app.dbAccess.models.DataDAO entry (don't flush the Session after an exception occurs)
org.hibernate.AssertionFailure: null id in my.app.dbAccess.models.DataDAO entry (don't flush the Session after an exception occurs)
    at org.hibernate.event.internal.DefaultFlushEntityEventListener.checkId(DefaultFlushEntityEventListener.java:60)
    at org.hibernate.event.internal.DefaultFlushEntityEventListener.getValues(DefaultFlushEntityEventListener.java:175)
    at org.hibernate.event.internal.DefaultFlushEntityEventListener.onFlushEntity(DefaultFlushEntityEventListener.java:135)
    at org.hibernate.event.internal.AbstractFlushingEventListener.flushEntities(AbstractFlushingEventListener.java:216)
    at org.hibernate.event.internal.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:85)
    at org.hibernate.event.internal.DefaultAutoFlushEventListener.onAutoFlush(DefaultAutoFlushEventListener.java:44)
    at org.hibernate.internal.SessionImpl.autoFlushIfRequired(SessionImpl.java:1251)
    at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1319)
    at org.hibernate.internal.QueryImpl.list(QueryImpl.java:87)
    at org.hibernate.jpa.internal.QueryImpl.list(QueryImpl.java:606)
    at org.hibernate.jpa.internal.QueryImpl.getSingleResult(QueryImpl.java:529)
    at org.springframework.data.jpa.repository.support.SimpleJpaRepository.count(SimpleJpaRepository.java:486)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.executeMethodOn(RepositoryFactorySupport.java:503)
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:488)
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:460)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:61)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:280)
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:136)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:133)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213)
    at com.sun.proxy.$Proxy137.count(Unknown Source)
    at my.app.dbAccess.generated.proxy.CountryRepositoryImpl.findByCountry_Id(CountryRepositoryImpl.java:800)
    at my.app.services.DataServiceImpl.getCountryFromId(DataServiceImpl.java:131)
    at my.app.services.DataServiceImpl.fromDao(DataServiceImpl.java:109)
    at my.app.services.DataServiceImpl.fromDao(DataServiceImpl.java:1)
    at my.app.services.DataServiceImpl.fromDao(DataServiceImpl.java:118)
    at my.app.services.DataServiceImpl.fromDao(DataServiceImpl.java:1)
    at my.app.services.DataServiceImpl$$FastClassBySpringCGLIB$$72be48ea.invoke(<generated>)
    at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
    at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:651)
    at my.app.services.DataServiceImpl$$EnhancerBySpringCGLIB$$c0525c49.fromDao(<generated>)
    at my.app.event.consumers.DataCreationListener.onPostInsert(DataCreationListener.java:40)
    at org.hibernate.action.internal.EntityIdentityInsertAction.postInsert(EntityIdentityInsertAction.java:156)
    at org.hibernate.action.internal.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:102)
    at org.hibernate.engine.spi.ActionQueue.execute(ActionQueue.java:597)

是不是因为我正在使用onPostInsert方法进行查询？从这种方法做查询不安全吗？我没有看到数据有任何问题，我的预感是它与hibernate envers有关，但我无法弄清楚。有人可以用正确的方式指出我。谢谢!!

Answer 1

是因为我正在使用onPostInsert方法进行查询吗？

可能的。从我看到的，从查询中触发了预先刷新。
您更有可能使用Hibernate生成的ID（很可能是生成的数据库）。

使用此方法进行查询是不安全的？

根据具体情况，可能不安全。
当然，它会破坏批量/批量插入，从而严重降低性能。

尝试暂停当前事务以防止刷新并在外部执行查询。
您可能会得到过时的结果，但在这种情况下这似乎不是问题。

在Spring中不知道怎么做，在JavaEE中你可以调用像EJB这样的方法：

@TransactionAttribute(TransactionAttributeType.NOT_SUPPORTED) // alternatively use REQUIRES_NEW
public Country getCountryFromId(Object id) {
    ....
}

我确定有一个等效弹簧。

我没有看到数据有任何问题，我的预感是它与hibernate envers有关，但我无法弄明白。

数据存在问题：ID为空 - 尚未分配。
我使用应用程序生成的ID（通常是UUID或SUID）来避免这类问题。

Envers也会对侦听器执行审计，但是ST中没有证据，我们没有首先运行哪个侦听器 - 你的或者Envers。

在这两种情况下，这似乎都无关紧要。我先检查其他事情（防止自动冲洗）。

Hibernate Envers：发生断言失败（这可能表示Hibernate中存在错误，但更可能是由于对会话的不安全使用）

1 个答案: