我有一个实体,它懒惰地初始化了一个Set,并且我还为该实体类添加了PropertyChangeSupport。下面是Set的setter方法:
public void setAskPrices(Set<AskPrice> askPrices) {
propertyChangeSupport.firePropertyChange(ASKPRICES_PROPERTY, this.askPrices,
this.askPrices = askPrices);
}
在我的代码的另一个地方,我构建了一个Criteria查询,并且希望它能够立即获取这个集合:
List<PriceRequest> pr = session.createCriteria(PriceRequest.class)
.setFetchMode("askPrices", FetchMode.JOIN)
.add(Restrictions.ilike("reqNum", "%" + reqNum + "%")).list();
当我运行上述查询时,Hibernate会抛出一个异常:
Caused by: org.hibernate.LazyInitializationException: failed to lazily initialize a collection, no session or session was closed
at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:383)
at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationExceptionIfNotConnected(AbstractPersistentCollection.java:375)
at org.hibernate.collection.AbstractPersistentCollection.readSize(AbstractPersistentCollection.java:122)
at org.hibernate.collection.PersistentSet.size(PersistentSet.java:162)
at java.util.AbstractSet.equals(AbstractSet.java:75)
at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:273)
at com.frc_agencies.model.persistent.PriceRequest.setAskPrices(PriceRequest.java:160)
经过调查,我发现firePropertyChange()函数会调用oldValu.equals(newValue)。在我的情况下,newValue是新的持久化集合。equals()函数会在某个时候对新的集合调用size(),然后size()会调用org.hibernate.collection.AbstractPersistentCollection.readSize(),代码如下:
protected boolean readSize() {
if (!initialized) {
if ( cachedSize!=-1 && !hasQueuedOperations() ) {
return true;
}
else {
throwLazyInitializationExceptionIfNotConnected();
CollectionEntry entry = session.getPersistenceContext().getCollectionEntry(this);
CollectionPersister persister = entry.getLoadedPersister();
if ( persister.isExtraLazy() ) {
if ( hasQueuedOperations() ) {
session.flush();
}
cachedSize = persister.getSize( entry.getLoadedKey(), session );
return true;
}
}
}
read();
return false;
}
异常在throwLazyInitializationExceptionIfNotConnected()方法中抛出。该方法调用以下方法:
/**
* Is the collection currently connected to an open session?
*/
private final boolean isConnectedToSession() {
return session!=null &&
session.isOpen() &&
session.getPersistenceContext().containsCollection(this);
}
当session.getPersistenceContext().containsCollection(this)返回false时,说明当前持久化集合不属于当前会话。
我决定进行一个实验。我删除了Criteria查询中的setFetchMode()调用,并且在查询调用返回后,我简单地调用了:
Hibernate.initialize(pr.getAskPrices());
这似乎很有效!
但我不想一直调用Hibernate.initialize()。有人能建议我可能如何使用原始的setFetchMode()调用来使其工作吗?
谢谢。
编辑: 发布相关映射
<set name="askPrices" table="ASK_PRICE" inverse="true" lazy="true" fetch="select" cascade="all-delete-orphan">
<meta attribute="bound">ASKPRICES_PROPERTY</meta>
<key on-delete="cascade">
<column name="REQ_ID" not-null="true" />
</key>
<one-to-many class="AskPrice" />
</set>