我在使用Hibernate保存新对象时遇到问题，Hibernate包含一个嵌套的集合，该集合在hibernate中映射为cascade="all, delete-orphan"。更具体地说，如果我保存祖父对象，它将失败，下面包含堆栈跟踪。
特别令人沮丧的是我们遇到过这个问题几次，但它并没有始终出现在我们坚持的所有集合中，只有其中一些并且我们不能很好地了解Hibernate以查看常见原因。非常感谢任何见解。
总的来说，我似乎经常在尝试跟踪错误发生时调试Hibernate的源代码，这对于这样一个成熟的库来说似乎很奇怪。这也是一个非常缓慢的过程，因为Hibernate内部对于那些只是试图使用它的人来说非常复杂。
我的对象类的缩写版本，hibernate映射文件和repro case包含在堆栈跟踪下面。
编辑：使用cascade="all"可以避免错误，但会失去我们宁愿拥有的功能。什么假设是删除孤立级联制作被违反？如果我从Hibernate的角度做了一些无效/非法的事情，我希望它根本不会持续存在，不仅在启用delete-orphan时失败。
com.foo.server.services.db.exception.InvalidObjectException: org.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing: com.foo.server.model.house.conditioning.Duct
at com.foo.server.services.db.Transaction.commit(Transaction.java:33)
at com.foo.server.services.db.service.PersistenceManager.commitTransactionIfOpen(PersistenceManager.java:83)
at com.foo.server.services.db.service.DataService.save(DataService.java:230)
at com.foo.server.services.db.service.DataService.save(DataService.java:188)
at com.foo.server.model.house.TestHousePlan_JDO.testAddDistributionSystemSave(TestHousePlan_JDO.java:55)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
at org.junit.rules.TestWatcher$1.evaluate(TestWatcher.java:55)
at org.junit.rules.RunRules.evaluate(RunRules.java:20)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)
Caused by: org.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing: com.foo.server.model.house.conditioning.Duct
at org.hibernate.engine.ForeignKeys.getEntityIdentifierIfNotUnsaved(ForeignKeys.java:242)
at org.hibernate.collection.AbstractPersistentCollection.getOrphans(AbstractPersistentCollection.java:919)
at org.hibernate.collection.PersistentList.getOrphans(PersistentList.java:70)
at org.hibernate.engine.CollectionEntry.getOrphans(CollectionEntry.java:373)
at org.hibernate.engine.Cascade.deleteOrphans(Cascade.java:364)
at org.hibernate.engine.Cascade.cascadeCollectionElements(Cascade.java:348)
at org.hibernate.engine.Cascade.cascadeCollection(Cascade.java:266)
at org.hibernate.engine.Cascade.cascadeAssociation(Cascade.java:243)
at org.hibernate.engine.Cascade.cascadeProperty(Cascade.java:193)
at org.hibernate.engine.Cascade.cascade(Cascade.java:154)
at org.hibernate.event.def.AbstractFlushingEventListener.cascadeOnFlush(AbstractFlushingEventListener.java:154)
at org.hibernate.event.def.AbstractFlushingEventListener.prepareEntityFlushes(AbstractFlushingEventListener.java:145)
at org.hibernate.event.def.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:88)
at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:49)
at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1028)
at com.foo.server.services.db.Transaction.commit(Transaction.java:28)
... 31 more
public class HousePlan
{
Long id;
List<DistributionSystem> distributionSystems = Lists.newArrayList();
// Other fields excluded
public HousePlan()
{
distributionSystems.add(new DistributionSystem());
}
// getters + setters
}
<hibernate-mapping package="com.foo.server.model.house">
<class name="HousePlan" table="house_plan">
<id name="id" column="id">
<generator class="native" />
</id>
<list name="distributionSystems" cascade="all,delete-orphan" lazy="false">
<key column="housePlanId" not-null="false" />
<list-index column="housePlanIndex" />
<one-to-many class="com.foo.server.model.house.conditioning.DistributionSystem" />
</list>
<!-- Other mappings excluded -->
</class>
</hibernate-mapping>
public class DistributionSystem
{
Long id;
List<Duct> ducts = Lists.newArrayList();
// Other fields excluded
public DistributionSystem()
{
ducts.add(new Duct());
ducts.add(new Duct());
}
// getters + setters excluded
}
<hibernate-mapping package="com.foo.server.model.house.conditioning">
<class name="DistributionSystem" table="distribution_system">
<id name="id" column="id">
<generator class="native" />
</id>
<!-- Note the usage of `cascade="all,delete-orphan"` which is the normal solution to this problem -->
<list name="ducts" cascade="all,delete-orphan" lazy="false">
<key column="distributionSystemId" not-null="false" />
<list-index column="distributionSystemIndex" />
<one-to-many class="com.foo.server.model.house.conditioning.Duct" />
</list>
<!-- Other mappings excluded -->
</class>
</hibernate-mapping>
public class Duct
{
Long id;
// Other fields excluded
// Constructor excluded
// getters + setters excluded
}
<hibernate-mapping package="com.foo.server.model.house.conditioning">
<class name="Duct" table="duct">
<id name="id" column="id">
<generator class="native" />
</id>
<!-- Other mappings excluded -->
</class>
</hibernate-mapping>
包括我们如何使用hibernate的缩写实现。
public class ReproCase
{
public static Session session = getSessionFactory().openSession();
public static void main(String... args)
{
HousePlan plan = new HousePlan();
// This save succeeds
plan = save(plan);
plan.getDistributionSystems().add(new DistributionSystem());
// This save fails
plan = save(plan);
}
public static <T> T save(T object)
{
Transaction transaction = new Transaction(session);
transaction.begin();
// In our full app our object inheritance hierarchy allows for the
// call to getId()
// Objects with null ids are transient. Objects with non-null ids are
// not transient, but might be detached from the persistence context so
// here we ensure the object is attached.
if (object.getId() != null)
{
object = (T)session.merge(object);
}
try
{
session.saveOrUpdate(object);
}
catch (Exception e)
{
session.merge(object);
}
// This is where the TransientObjectException occurs
session.flush();
transaction.commit();
return object;
}
}
答案 0 :(得分：0)
您应该删除列表的实例化：
List<Duct> ducts = Lists.newArrayList();
这种关系由Hibernate管理（通过代理），它将无法处理标准List ......
这显然意味着您无法在构造函数中添加值，您必须等到Hibernate在添加默认值之前知道父级：
DistributionSystem ds = save(new DistributionSystem());
ds.getDucts().add(new Duct());
ds.getDucts().add(new Duct());
ds.getDucts().add(new Duct());
ds = save(new DistributionSystem());