hibernate映射-单向n-n关联关系

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hibernate映射-多对多关联关系

n-n关联必须使用连接表才能完成，

一、代码示例：

{类文件↓}

Category.class

 1 package com.zit.hibernate.n2n;
 2 
 3 import java.util.HashSet;
 4 import java.util.Set;
 5 
 6 public class Category {
 7     
 8     private Integer id;
 9     private String name;
10     
11     private Set<Item> items = new HashSet<>();
12     
13     public Integer getId() {
14         return id;
15     }
16     public void setId(Integer id) {
17         this.id = id;
18     }
19     public String getName() {
20         return name;
21     }
22     public void setName(String name) {
23         this.name = name;
24     }
25     public Set<Item> getItems() {
26         return items;
27     }
28     public void setItems(Set<Item> items) {
29         this.items = items;
30     }
31     
32 }

Category.class

Item.class

 1 package com.zit.hibernate.n2n;
 2 
 3 public class Item {
 4     
 5     private Integer id;
 6     private String name;
 7     
 8     public Integer getId() {
 9         return id;
10     }
11     public void setId(Integer id) {
12         this.id = id;
13     }
14     public String getName() {
15         return name;
16     }
17     public void setName(String name) {
18         this.name = name;
19     }
20     
21 }

Item.class

(单向n-n)

{映射文件↓}

Item.hbm.xml

 1 <?xml version="1.0"?>
 2 <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
 3 "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
 4 <!-- Generated 2015-12-25 13:55:35 by Hibernate Tools 3.4.0.CR1 -->
 5 <hibernate-mapping package="com.zit.hibernate.n2n">
 6     <class name="Item" table="ITEMS">
 7         <id name="id" type="java.lang.Integer">
 8             <column name="ID" />
 9             <generator class="native" />
10         </id>
11         <property name="name" type="java.lang.String">
12             <column name="NAME" />
13         </property>
14     </class>
15 </hibernate-mapping>

Item.hbm.xml

Category.hbm.xml

 1 <?xml version="1.0"?>
 2 <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
 3 "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
 4 <!-- Generated 2015-12-25 13:55:35 by Hibernate Tools 3.4.0.CR1 -->
 5 <hibernate-mapping package="com.zit.hibernate.n2n">
 6     <class name="Category" table="CATEGORIES">
 7         <id name="id" type="java.lang.Integer">
 8             <column name="ID" />
 9             <generator class="native" />
10         </id>
11         <property name="name" type="java.lang.String">
12             <column name="NAME" />
13         </property>
14         <set name="items" table="CATEGORIES_ITEMS">
15             <key>
16                 <column name="C_ID" />
17             </key>
18             <many-to-many class="Item" column="I_ID"></many-to-many>
19         </set>
20     </class>
21 </hibernate-mapping>

Category.hbm.xml

在Category.hbm.xml中，

1 <set name="items" table="CATEGORIES_ITEMS">
2    <key>
3       <column name="C_ID" />
4    </key>
5    <many-to-many class="Item" column="I_ID"></many-to-many>
6 </set>