休眠JPA级联删除问题

Question

为了解释我的问题，我用两个表创建了这个简单的项目：item和order1（带有orderId作为外键的项目）。

现在，当我试图从订单表中删除一行时，我收到错误，说特定的订单ID与'item'表中的少数项目相关联。因此，我所做的是我遍历所有项目对象（使用'Eager'加载），并为它们中的每一个调用destroy（）。删除所有项目后，我打电话给order.destroy（）。 但现在，我得到以下错误：

Exception in thread "main" javax.persistence.RollbackException: Error while commiting the transaction 
     at org.hibernate.ejb.TransactionImpl.commit(TransactionImpl.java:71) 
     at  com.sourind.test.testorm.controller.ItemJpaController.destroy(ItemJpaController.java:112) 
     at com.sourind.test.testorm.App.main(App.java:31) 
Caused by: org.hibernate.ObjectDeletedException: deleted entity passed to persist:  [com.sourind.test.testorm.entity.Item#<null>] 

我使用Hibernate（JPA 2.0）。任何帮助在这个问题将不胜感激。

仅供参考，我复制通过NetBeans中创建的实体类：}

@Entity 
@Table(name = "item", catalog = "test", schema = "") 
@NamedQueries({ 
@NamedQuery(name = "Item.findAll", query = "SELECT i FROM Item i"), 
@NamedQuery(name = "Item.findById", query = "SELECT i FROM Item i WHERE i.id = :id"), 
@NamedQuery(name = "Item.findByName", query = "SELECT i FROM Item i WHERE i.name = :name")}) 
public class Item implements Serializable { 
    private static final long serialVersionUID = 1L; 
    @Id 
    @GeneratedValue(strategy = GenerationType.IDENTITY) 
    @Basic(optional = false) 
    @Column(name = "id") 
    private Integer id; 
    @Basic(optional = false) 
    @Column(name = "name") 
    private String name; 
    @JoinColumn(name = "orderId", referencedColumnName = "id") 
    @ManyToOne(optional = false) 
    private Order1 order1; 

    public Item() { 
    } 

    public Item(Integer id) { 
     this.id = id; 
    } 

public Item(Integer id, String name) { 
    this.id = id; 
    this.name = name; 
} 

public Integer getId() { 
    return id; 
} 

public void setId(Integer id) { 
    this.id = id; 
} 

public String getName() { 
    return name; 
} 

public void setName(String name) { 
    this.name = name; 
} 

public Order1 getOrder1() { 
    return order1; 
} 

public void setOrder1(Order1 order1) { 
    this.order1 = order1; 
} 

@Override 
public int hashCode() { 
    int hash = 0; 
    hash += (id != null ? id.hashCode() : 0); 
    return hash; 
} 

@Override 
public boolean equals(Object object) { 
    // TODO: Warning - this method won't work in the case the id fields are not set 
    if (!(object instanceof Item)) { 
     return false; 
    } 
    Item other = (Item) object; 
    if ((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))) { 
     return false; 
    } 
    return true; 
} 

@Override 
public String toString() { 
    return "com.sourind.test.testorm.entity.Item[id=" + id + "]"; 
} 

而且order1类：

@Entity 
@Table(name = "order", catalog = "test", schema = "") 
@NamedQueries({ 
    @NamedQuery(name = "Order1.findAll", query = "SELECT o FROM Order1 o"), 
    @NamedQuery(name = "Order1.findById", query = "SELECT o FROM Order1 o WHERE o.id = :id"), 
    @NamedQuery(name = "Order1.findByOrderDate", query = "SELECT o FROM Order1 o WHERE o.orderDate = :orderDate")}) 
public class Order1 implements Serializable { 
    private static final long serialVersionUID = 1L; 
    @Id 
    @GeneratedValue(strategy = GenerationType.IDENTITY) 
    @Basic(optional = false) 
    @Column(name = "id") 
    private Integer id; 
    @Basic(optional = false) 
    @Column(name = "orderDate") 
    @Temporal(TemporalType.TIMESTAMP) 
private Date orderDate; 
@OneToMany(cascade = CascadeType.ALL, mappedBy = "order1", fetch=FetchType.EAGER) 
private List<Item> itemList; 

public Order1() { 
} 

public Order1(Integer id) { 
    this.id = id; 
} 

public Order1(Integer id, Date orderDate) { 
    this.id = id; 
    this.orderDate = orderDate; 
} 

public Integer getId() { 
    return id; 
} 

public void setId(Integer id) { 
    this.id = id; 
} 

public Date getOrderDate() { 
    return orderDate; 
} 

public void setOrderDate(Date orderDate) { 
    this.orderDate = orderDate; 
} 

public List<Item> getItemList() { 
    return itemList; 
} 

public void setItemList(List<Item> itemList) { 
    this.itemList = itemList; 
} 

@Override 
public int hashCode() { 
    int hash = 0; 
    hash += (id != null ? id.hashCode() : 0); 
    return hash; 
} 

@Override 
public boolean equals(Object object) { 
    // TODO: Warning - this method won't work in the case the id fields are not set 
    if (!(object instanceof Order1)) { 
     return false; 
    } 
    Order1 other = (Order1) object; 
    if ((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))) { 
     return false; 
    } 
    return true; 
} 

@Override 
public String toString() { 
    return "com.sourind.test.testorm.entity.Order1[id=" + id + "]"; 
} 

}

在此先感谢， Souri

Answer 1

您应该只能删除订单记录并删除所有关联的物料记录。要做到这一点，你需要添加另一个级联类型的订单和项目之间的关联。

@OneToMany(cascade=CascadeType.ALL, mappedBy = "order1", fetch=FetchType.EAGER, orphanRemoval=true) 
private List<Item> itemList; 

这告诉休眠当你删除父命令它应该删除子项目记录。

session.delete(order); 

此删除将级联到子项目记录并将其删除。

Answer 2

@Alex这里是ItemJpaController#destroy()

public void destroy(Integer id) throws NonexistentEntityException { 
    EntityManager em = null; 
    try { 
     em = getEntityManager(); 
     em.getTransaction().begin(); 
     Item item; 
     try { 
      item = em.getReference(Item.class, id); 
      item.getId(); 
     } catch (EntityNotFoundException enfe) { 
      throw new NonexistentEntityException("The item with id " + id + " no longer exists.", enfe); 
     } 
     Order1 order1 = item.getOrder1(); 
     if (order1 != null) { 
      order1.getItemList().remove(item); 
      order1 = em.merge(order1); 
     } 
     em.remove(item); 
     em.getTransaction().commit(); 
    } finally { 
     if (em != null) { 
      em.close(); 
     } 
    } 
} 

还有，我现在用的没有DELETE_ORPHAN级联型休眠的版本的代码。

另外，如何获得会话？并且我应该在方法中的JpaController类中或者在创建/删除对象的邮件方法中获得它。