问题描述
实体类
客户
@Entity
@Table(name="Custumer")
public class Custumer implements Serializable {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name="id")
private Long id;
@Column(name="name",unique = true)
private String name;
@Column(name="Email",unique = true)
private String Email;
@Column(name = "Coins")
private Double coins;
@ManyToMany(fetch = FetchType.EAGER,cascade = CascadeType.ALL)
private List<ShippingAdress> shippingAdress = new ArrayList<ShippingAdress>();
@OneToMany( fetch = FetchType.EAGER, mappedBy = "custumer", cascade = CascadeType.ALL,orphanRemoval = true)
private List<Order> orders= new LinkedList<Order>();
//...
ShippingAdress
@Entity
@Table(name="ShippingAdress")
public class ShippingAdress implements Serializable {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name="id")
private Long id;
@Column(name="postCode")
private String PostCode;
@Column(name="street")
private String street;
@Column(name="house")
private String house;
@Column(name="flat")
private String flat;
@ManyToMany(mappedBy = "shippingAdress")
private List<Custumer> custumers = new LinkedList<Custumer>();
//...
项目
@Entity
@Table(name="Items")
public class Items implements Serializable,Comparable<Items> {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name="id")
private Long id;
@Column(name="name", unique = true)
private String name;
@Column(name="price")
private double price;
@Column(name="count")
private int count;
@OneToMany(mappedBy = "item", cascade = CascadeType.ALL,orphanRemoval = true)
List<Order> orders = new LinkedList<Order>();
//...
CustomerOrder
@Entity
@Table(name = "CustumerOrder")
public class Order implements Serializable {
@Id
@ManyToOne
private Custumer custumer;
@Id
@ManyToOne
private Items item;
当我尝试获取特定客户的所有订单
When I'm trying to get all orders from particular customer
public List<Order> getOrderByCustumerId(Custumer custumer) {
Criteria criteria = session.createCriteria(Order.class);
List<Order> res = (List<Order>) criteria.add(Restrictions.eq("custumer",custumer)).list();
return res;
}
我面临以下异常:
org.hibernate.loader.MultipleBagFetchException: cannot simultaneously fetch multiple bags
如果从它们存在的位置之一删除 fetch = FetchType.EAGER
得到以下内容:(假定已从客户中删除)
If delete fetch = FetchType.EAGER
from one of the places they are existed getting the following:(supposed deleted from customer )
org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: org.CoinsShop.DataBase.DataSets.Custumer.shippingAdress, could not initialize proxy - no Session
数据库中的关系
推荐答案
有个例外告诉您,您不能同时获取两个相关的收藏或包.一种快速的解决方案是从一个集合中删除 FetchType.EAGER
,并强制显式调用该集合对象来获取该集合.
As the exception says to you, you can't fetch two related collections or bags simultaneously. A quick solution would be to remove the FetchType.EAGER
from one collection and force the fetching of that collection explicitly calling the collection objects.
例如,如果从 shippingAddress
集合中删除 FetchType.EAGER
,则可以这样强制执行:
For example, if you remove the FetchType.EAGER
from shippingAddress
collection, you can force the fetching like this:
public List<Order> getOrderByCustomerId(Customer customer) {
Criteria criteria = session.createCriteria(Order.class);
List<Order> res = (List<Order>) criteria.add(Restrictions.eq("customer",customer)).list();
for (Order order : res)
order.getCustomer().getShippingAddress().size();
return res;
}
调用集合的 size()
方法将强制获取该集合的所有元素.
Calling the size()
method of the collection will force the fetching of all the elements of that collection.
有关此主题的更多信息:
More information about this topic:
这篇关于Hibernate:org.hibernate.loader.MultipleBagFetchException:无法同时获取多个包的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!