Google app engine 拥有一对多现场can'；不能突然修改-DatastoreRelationFieldManager.checkForParentSwitch中的ClassCastException

我的网络应用突然不允许人们购买我们的产品。我不知道该怎么办

昨晚，我们的一位工程师意外地从一个拥有的一对多字段（在父类中）中删除了

@Persistent

标记。他在没有测试的情况下将其上传到App Engine服务器。我们收到报告说人们买不到东西，所以我们查看了变化，进入并恢复了

@Persistent

标签

但是现在，每当代码试图修改该字段时，我们都会得到一个异常

请帮助-我不知道该怎么办-我们已经添加了

@Persistent

注释-为什么会发生此异常

@PersistenceCapable
public class Published {
    @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
    @PrimaryKey
    private Long id;

    ...
    // see note about this field above
    @Persistent(defaultFetchGroup = "true", mappedBy = "pub")
    private List<License> licenses;
    ...
}


@PersistenceCapable
public class License {
    @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
    @PrimaryKey
    private Key id;
    @Persistent
    private Published pub;
    ...
}

---

看起来应用程序引擎错误阻止我上载代码。一旦GAE赶上并切换到新代码，一切都很好

---

对于记录，我不确定是什么修复了它-它可能只是添加了

@Persistent

注释，或者它可能正在更改

Published.id

作为

键而不是
长的
列表是默认的Persistent FWIW，因此与此无关
Uncaught exception from servlet
java.lang.ClassCastException: java.lang.Long cannot be cast to java.lang.String
    at org.datanucleus.store.appengine.DatastoreRelationFieldManager.checkForParentSwitch(DatastoreRelationFieldManager.java:203)
    at org.datanucleus.store.appengine.DatastoreRelationFieldManager$1.setObjectViaMapping(DatastoreRelationFieldManager.java:134)
    at org.datanucleus.store.appengine.DatastoreRelationFieldManager$1.apply(DatastoreRelationFieldManager.java:113)
    at org.datanucleus.store.appengine.DatastoreRelationFieldManager.storeRelations(DatastoreRelationFieldManager.java:82)
    at org.datanucleus.store.appengine.DatastoreFieldManager.storeRelations(DatastoreFieldManager.java:959)
    at org.datanucleus.store.appengine.DatastorePersistenceHandler.storeRelations(DatastorePersistenceHandler.java:585)
    at org.datanucleus.store.appengine.DatastorePersistenceHandler.insertPostProcess(DatastorePersistenceHandler.java:320)
    at org.datanucleus.store.appengine.DatastorePersistenceHandler.insertObjects(DatastorePersistenceHandler.java:272)
    at org.datanucleus.store.appengine.DatastorePersistenceHandler.insertObject(DatastorePersistenceHandler.java:256)
    at org.datanucleus.state.JDOStateManagerImpl.internalMakePersistent(JDOStateManagerImpl.java:3185)
    at org.datanucleus.state.JDOStateManagerImpl.makePersistent(JDOStateManagerImpl.java:3161)
    at org.datanucleus.ObjectManagerImpl.persistObjectInternal(ObjectManagerImpl.java:1298)
    at org.datanucleus.sco.SCOUtils.validateObjectForWriting(SCOUtils.java:1476)
    at org.datanucleus.store.mapped.scostore.ElementContainerStore.validateElementForWriting(ElementContainerStore.java:380)
    at org.datanucleus.store.mapped.scostore.FKListStore.validateElementForWriting(FKListStore.java:609)
    at org.datanucleus.store.mapped.scostore.FKListStore.internalAdd(FKListStore.java:344)
    at org.datanucleus.store.appengine.DatastoreFKListStore.internalAdd(DatastoreFKListStore.java:146)
    at org.datanucleus.store.mapped.scostore.AbstractListStore.add(AbstractListStore.java:105)
    at org.datanucleus.sco.backed.List.add(List.java:649)
    at (my servlet)