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google app engine-org.datanucleus.exceptions.nucleusereexception:对象管理器已关闭

datanucleus jpa google-app-engine spring java

Taylor Leese · 技术社区 · 15 年前

为什么下面的代码会导致org.datanucleus.exceptions.nucleusereexception:对象管理器已关闭?异常似乎在query.getResultList()处引发。

public final void removeUserTokens(final String username) {
    final Query query = entityManager.createQuery(
        "SELECT p FROM PersistentLogin p WHERE username = :username");
    query.setParameter("username", username);

    for (Object token : query.getResultList()) {
        entityManager.remove(token);
    }
}

例外:

org.datanucleus.exceptions.NucleusUserException: Object Manager has been closed
 at org.datanucleus.ObjectManagerImpl.assertIsOpen(ObjectManagerImpl.java:3876)
 at org.datanucleus.ObjectManagerImpl.getFetchPlan(ObjectManagerImpl.java:376)
 at org.datanucleus.store.query.Query.getFetchPlan(Query.java:497)
 at org.datanucleus.store.appengine.query.DatastoreQuery$6.apply(DatastoreQuery.java:611)
 at org.datanucleus.store.appengine.query.DatastoreQuery$6.apply(DatastoreQuery.java:610)
 at org.datanucleus.store.appengine.query.LazyResult.resolveNext(LazyResult.java:94)
 at org.datanucleus.store.appengine.query.LazyResult$LazyAbstractListIterator.computeNext(LazyResult.java:215)
 at org.datanucleus.store.appengine.query.AbstractIterator.tryToComputeNext(AbstractIterator.java:132)
 at org.datanucleus.store.appengine.query.AbstractIterator.hasNext(AbstractIterator.java:127)
 at org.datanucleus.store.appengine.query.LazyResult$AbstractListIterator.hasNext(LazyResult.java:169)
 at com.mystuff.service.auth.PersistentTokenRepositoryImpl.removeUserTokens(PersistentTokenRepositoryImpl.java:90)

编辑 :我增加了DataNucleus的日志级别,这就是我看到的。

FINE: Object Manager "org.datanucleus.ObjectManagerImpl@5d8d3d6c" opened for datastore "org.datanucleus.store.appengine.DatastoreManager@2447e380"
Feb 25, 2010 7:21:38 AM org.datanucleus.ObjectManagerImpl initialiseLevel1Cache
FINE: Level 1 Cache of type "weak" initialised
Feb 25, 2010 7:21:38 AM org.datanucleus.JDOClassLoaderResolver classForName
FINE: Class "java.lang.PersistentLogin" was not found in the CLASSPATH [Class resolver called from org.datanucleus.util.Imports.resolveClassDeclaration (line=177)]
Feb 25, 2010 7:21:38 AM org.datanucleus.ObjectManagerImpl disconnectSMCache
FINE: Level 1 Cache cleared
Feb 25, 2010 7:21:38 AM org.datanucleus.ObjectManagerImpl postClose
FINE: Object Manager "org.datanucleus.ObjectManagerImpl@5d8d3d6c" closed
Feb 25, 2010 7:21:38 AM com.google.apphosting.utils.jetty.JettyLogger warn
WARNING: /j_spring_security_logout
Object Manager has been closed
org.datanucleus.exceptions.NucleusUserException: Object Manager has been closed
 at org.datanucleus.ObjectManagerImpl.assertIsOpen(ObjectManagerImpl.java:3876)
 at org.datanucleus.ObjectManagerImpl.getFetchPlan(ObjectManagerImpl.java:376)

3 回复 | 直到 10 年前

Taylor Leese 15 年前

添加 @Transactional 方法阻止对象管理器关闭。但是,我不知道没有这个为什么它会关闭。

Thilo 15 年前

我不知道为什么,但这似乎与 query.getResultList() 懒惰的装填。很明显,当你打电话的时候,懒惰的负载会崩溃。 remove(token) .

作为一种解决方案,您能否先收集数组列表中元素的ID/键,然后在单独的循环中将它们从数据存储中删除?

alexis 14 年前

对我有效的解决方案和我在这里发现的bug的描述:

http://groups.google.com/group/google-appengine-java/browse_thread/thread/945f6ca66c1c587e