Google App Engine - org.datanucleus.exceptions.NucleusUserException：对象管理器已关闭 [英] Google App Engine - org.datanucleus.exceptions.NucleusUserException: Object Manager has been closed

问题描述

为什么下面的代码会导致org.datanucleus.exceptions.NucleusUserException：对象管理器已关闭？这个异常似乎是在query.getResultList（）引发的。

  public final void removeUserTokens（final String username）{
查询query = entityManager.createQuery（
SELECT p FROM PersistentLogin p WHERE username =：username）; 
 query.setParameter（username，username）; 
 
 for（Object token：query.getResultList（））{
 entityManager.remove（token）; 
 
 
 code 
 
 $ b $例外
 
 
  org.datanucleus.exceptions.NucleusUserException：Object Manager已关闭
 at org.datanucleus.ObjectManagerImpl.assertIsOpen（ObjectManagerImpl.java:3876）
在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（Abs 
 at org.datanucleus.store.appengine.query.LazyResult $ AbstractListIterator.hasNext（LazyResult.java:169）
 at com.mystuff.service.auth.PersistentTokenRepositoryImpl.removeUserTokens（ PersistentTokenRepositoryImpl.java:90）
  
 编辑：我增加了日志级别datanucleus，这就是我所看到的。
  FINE：对象管理器org.datanucleus.ObjectManagerImpl@5d8d3d6c为数据存储打开org .datanucleus.store.appengine.DatastoreManager @ 2447e380
 2010年2月25日上午7时21分38秒org.datanucleus.ObjectManagerImpl initialiseLevel1Cache 
 FINE：1级缓存类型弱初始化
 2010年2月25日上午7时21分38秒org.datanucleus.JDOClassLoaderResolver classForName 
 FINE：在CLASSPATH中找不到类java.lang.PersistentLogin[从org.datanucleus.util.Imports.resolveClassDeclaration调用的类解析器（line = 177）] 
 2010年2月25日7:21:38 org.datanucleus.ObjectManagerImpl d isconnectSMCache 
 FINE：清除1级缓存
 2010年2月25日7:21:38 org.datanucleus.ObjectManagerImpl postClose 
 FINE：Object Managerorg.datanucleus.ObjectManagerImpl@5d8d3d6cclosed 
 Feb 25，2010 7:21:38 AM com.google.apphosting.utils.jetty.JettyLogger警告
警告：/ j_spring_security_logout 
对象管理器已关闭
 org.datanucleus。异常.NucleusUserException：对象管理器已关闭
 at org.datanucleus.ObjectManagerImpl.assertIsOpen（ObjectManagerImpl.java:3876）
 at org.datanucleus.ObjectManagerImpl.getFetchPlan（ObjectManagerImpl.java:376）
  
 
 
解决方案 
添加 @Transactional  
Why does the code below result in org.datanucleus.exceptions.NucleusUserException: Object Manager has been closed? The exception appears to be thrown at query.getResultList().
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);
    }
}          
Exception:
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)
Edit: I increased the log level for datanucleus and this is what I see.
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)

解决方案
Adding @Transactional to the method prevents the object manager from closing. However, I'm not sure why it closes without this.


                        
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