Hibernate不会向公众公开其内部信息，因此您不会在公共API中找到要搜索的内容。但是，您可以在Hibernate接口的实现类中找到答案：此方法（摘自http://pre.google.com/p/bo2/source/browse/trunk/Bo2ImplHibernate/main/gr/interamerican/bo2/
impl / open / hibernate /
HibernateBo2Utils.java）将告知会话中是否存在对象：
public static Object getFromSession (Serializable identifier, Class<?> clazz, Session s) { String entityName = clazz.getName(); if(identifier == null) { return null; } SessionImplementor sessionImpl = (SessionImplementor) s; EntityPersister entityPersister = sessionImpl.getFactory().getEntityPersister(entityName); PersistenceContext persistenceContext = sessionImpl.getPersistenceContext(); EntityKey entityKey = new EntityKey(identifier, entityPersister, EntityMode.POJO); Object entity = persistenceContext.getEntity(entityKey); return entity; }如果进一步深入研究，您将看到PersistenceContext的唯一实现是org.hibernate.engine.StatefulPersistenceContext。此类具有以下集合：
// Loaded entity instances, by EntityKeyprivate Map entitiesByKey;// Loaded entity instances, by EntityUniqueKeyprivate Map entitiesByUniqueKey;// Identity map of EntityEntry instances, by the entity instanceprivate Map entityEntries;// Entity proxies, by EntityKeyprivate Map proxiesByKey;// Snapshots of current database state for entities// that have *not* been loadedprivate Map entitySnapshotsByKey;// Identity map of array holder ArrayHolder instances, by the array instanceprivate Map arrayHolders;// Identity map of CollectionEntry instances, by the collection wrapperprivate Map collectionEntries;// Collection wrappers, by the CollectionKeyprivate Map collectionsByKey; //key=CollectionKey, value=PersistentCollection// Set of EntityKeys of deleted objectsprivate HashSet nullifiableEntityKeys;// properties that we have tried to load, and not found in the databaseprivate HashSet nullAssociations;// A list of collection wrappers that were instantiating during result set// processing, that we will need to initialize at the end of the queryprivate List nonlazyCollections;// A container for collections we load up when the owning entity is not// yet loaded ... for now, this is purely transient!private Map unownedCollections;// Parent entities cache by their child for cascading// May be empty or not contains all relation private Map parentsByChild;
因此，您需要做的是将PersistenceContext强制转换为StatefulPersistenceContext，然后使用反射来获取所需的私有集合，然后对其进行迭代。
我强烈建议您仅在调试代码上执行此操作。这不是公共API，它可能会因较新的Hibernate版本而制止。
