【发布时间】：2011-03-13 08:48:13
【问题描述】：
我有一个基本的一对多关系父/子，就像在 Hibernate 参考书的第 21 章中一样。
级联仅从子级到父级（仅保留级联，因为如果我删除子级，我不想删除父级）。
当我将孩子添加到父母并保存孩子时，我有一个 TransientObjectException...
@Entity
public class Parent implements Serializable {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
@OneToMany(mappedBy = "parent", orphanRemoval = true)
private List<Child> childs;
public List<Child> getChilds() {
return childs;
}
public void setChilds(List<Child> childs) {
this.childs = childs;
}
public void addChild(Child child) {
if (childs == null) childs = new ArrayList<Child>();
if (childs.add(child)) child.setParent(this);
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
}
@Entity
public class Child implements Serializable {
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;
@ManyToOne(optional = false)
@Cascade( { PERSIST, MERGE, REFRESH, SAVE_UPDATE, REPLICATE, LOCK, DETACH })
private Parent parent;
public Parent getParent() {
return parent;
}
public void setParent(Parent parent) {
this.parent = parent;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
}
@Test
public void test() {
Parent parent = new Parent();
Child child = new Child();
parent.addChild(child);
genericDao.saveOrUpdate(child);
}
但是在 saveOrUpdate 上，我有这个例外：
org.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing: Child
at org.hibernate.engine.ForeignKeys.getEntityIdentifierIfNotUnsaved(ForeignKeys.java:244)
at org.hibernate.collection.AbstractPersistentCollection.getOrphans(AbstractPersistentCollection.java:911)
at org.hibernate.collection.PersistentBag.getOrphans(PersistentBag.java:143)
at org.hibernate.engine.CollectionEntry.getOrphans(CollectionEntry.java:373)
at org.hibernate.engine.Cascade.deleteOrphans(Cascade.java:471)
at org.hibernate.engine.Cascade.cascadeCollectionElements(Cascade.java:455)
at org.hibernate.engine.Cascade.cascadeCollection(Cascade.java:362)
at org.hibernate.engine.Cascade.cascadeAssociation(Cascade.java:338)
at org.hibernate.engine.Cascade.cascadeProperty(Cascade.java:204)
at org.hibernate.engine.Cascade.cascade(Cascade.java:161)
at org.hibernate.event.def.AbstractSaveEventListener.cascadeAfterSave(AbstractSaveEventListener.java:476)
at org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:354)
at org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:204)
at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:130)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:210)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:195)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.performSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:117)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:93)
at org.hibernate.impl.SessionImpl.fireSaveOrUpdate(SessionImpl.java:677)
at org.hibernate.impl.SessionImpl.saveOrUpdate(SessionImpl.java:669)
at org.hibernate.engine.CascadingAction$5.cascade(CascadingAction.java:252)
at org.hibernate.engine.Cascade.cascadeToOne(Cascade.java:392)
at org.hibernate.engine.Cascade.cascadeAssociation(Cascade.java:335)
at org.hibernate.engine.Cascade.cascadeProperty(Cascade.java:204)
at org.hibernate.engine.Cascade.cascade(Cascade.java:161)
at org.hibernate.event.def.AbstractSaveEventListener.cascadeBeforeSave(AbstractSaveEventListener.java:451)
at org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:288)
at org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:204)
at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:130)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:210)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:195)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.performSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:117)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:93)
at org.hibernate.impl.SessionImpl.fireSaveOrUpdate(SessionImpl.java:677)
at org.hibernate.impl.SessionImpl.saveOrUpdate(SessionImpl.java:669)
at org.hibernate.impl.SessionImpl.saveOrUpdate(SessionImpl.java:665)
我真的不明白，因为拯救孩子应该通过级联拯救父母...... 有什么想法吗？
更新 1
这个问题似乎与“orphanRemoval”有关，因为如果我在父级上发表评论：
@OneToMany(mappedBy = "parent" /*, orphanRemoval = true */)
private List<Child> childs;
有效！
它拯救了孩子，然后是父母。
但是当我从父级中删除一个孩子时，我真的需要通过级联删除孤儿。
更新 2
我创建了一个 JIRA 问题：
http://opensource.atlassian.com/projects/hibernate/browse/HHH-5364
更新 3
它似乎已修复:-)
http://opensource.atlassian.com/projects/hibernate/browse/HHH-2269
【问题讨论】：
-
欢迎来到 Stack Overflow！将来使用带有 0 和 1 的按钮来正确格式化您的代码（我已为您格式化）。
-
谢谢...我们同时做到了 ;-)
-
如果先救父母再救孩子会怎样？
-
它可以工作，但我不能在我的应用程序中这样做。孩子们在其他实体中使用并通过级联保存......这就是为什么我想在孩子们被保存时也保存他们的父母。
标签： java hibernate one-to-many cascade orphan