Hibernate JPA级联删除问题

问题描述

| 为了说明我的问题，我创建了一个带有两个表的简单项目：item和order1（其中orderId作为外键的项目）。 现在，当我尝试从订单表中删除一行时，出现错误，指出特定的订单ID与\'item \'表中的少量商品相关联。 因此，我要做的是遍历所有项目对象（使用\'Eager \'加载），并为每个对象调用destroy（）。删除所有项目后，我调用order.destroy（）。 但是现在，我收到以下错误：

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>]

我正在使用Hibernate（JPA 2.0）。在这方面的任何帮助将不胜感激。 作为参考，我正在复制netbeans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 + \"]\";
}

} 和order1类：

@Entity
@Table(name = \"order\",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 + \"]\";
}

} 提前致谢， 苏里     

解决方法

@Alex这是ѭ3code的代码

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();
        }
    }
}

而且，我使用的休眠版本没有

DELETE_ORPHAN

级联类型。 另外，我如何获得会议？我应该在

destroy()

方法中的

JpaController

类中还是在我从中创建/删除对象的mail方法中获取它？     ,您应该只能够删除订单记录，并删除所有关联的项目记录。为此，您需要向订单和商品之间的关联添加另一种层叠类型。

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

这告诉休眠状态，当您删除父订单时，它应该删除子项记录。

session.delete(order);

此删除操作将层叠到子Item记录并将其删除。