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我在 JBoss AS 7.1 上使用 Hibernate，在创建新实体并将现有实体设置为 ManyToOne 关系时遇到问题。在使用以下代码之前查询现有实体（客户）：

TypedQuery<Customer> query = em.createNamedQuery("Customer.findByLastNameLike", Customer.class);
query.setParameter("lastName", "%"+lastName+"%");
return query.getResultList();

当我在设置为 order后em.persist(order)在新实体上执行时，会引发以下异常：ordercustomerorder.setCustomer(customer)

Caused by: org.hibernate.PersistentObjectException: detached entity passed to persist: erp.model.persons.Customer
    at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:141)
    at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:717)
    at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:710)
    at org.hibernate.engine.spi.EJB3CascadingAction$1.cascade(EJB3CascadingAction.java:49)
    at org.hibernate.engine.internal.Cascade.cascadeToOne(Cascade.java:380)
    at org.hibernate.engine.internal.Cascade.cascadeAssociation(Cascade.java:323)
    at org.hibernate.engine.internal.Cascade.cascadeProperty(Cascade.java:208)
    at org.hibernate.engine.internal.Cascade.cascade(Cascade.java:165)
    at org.hibernate.event.internal.AbstractSaveEventListener.cascadeBeforeSave(AbstractSaveEventListener.java:437)
    at org.hibernate.event.internal.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:266)
    at org.hibernate.event.internal.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:195)
    at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:138)
    at org.hibernate.ejb.event.EJB3PersistEventListener.saveWithGeneratedId(EJB3PersistEventListener.java:78)
    at org.hibernate.event.internal.DefaultPersistEventListener.entityIsTransient(DefaultPersistEventListener.java:208)
    at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:151)
    at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:78)
    at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:725)
    at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:701)
    at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:705)
    at org.hibernate.ejb.AbstractEntityManagerImpl.persist(AbstractEntityManagerImpl.java:853)

实体定义如下：

@Entity
public class Order extends AbstractEntity implements Serializable {

    private static final long serialVersionUID = -8061887078955032972L;

    @ManyToOne(cascade={CascadeType.MERGE, CascadeType.REFRESH, CascadeType.PERSIST}, optional = false)
    private Customer customer = null;

@Entity
@DiscriminatorValue("customer")
public class Customer extends Person implements Serializable {

    private static final long serialVersionUID = 2788107135840578322L;

    @OneToMany(cascade=CascadeType.ALL, mappedBy="customer")
    private List<Order> orders = null;

在这种情况下有什么问题？

感谢您的任何提示...

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1 回答 1

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以下答案也回答了我的问题。我从使用更改em.persist()为em.merge()甚至用于新实体。现在我的整个对象图都成功地持久化了，无论是否混合了新实体。

JPA 级联持续存在并且对分离实体的引用会引发 PersistentObjectException。为什么？

此外，我删除了CascadeType.PERSIST

于 2012-09-03T21:56:29.027 回答