多对多的双向关联

老师(Teacher)知道自己教了哪些学生(Student)，学生(Student)也知道教自己的有哪些老师(Teacher)

　　Annotation 配置:

　　　　Teacher:　　　　　　

 1 package com.bjsxt.hibernate;
 2 
 3 import java.util.HashSet;
 4 import java.util.Set;
 5 
 6 import javax.persistence.Entity;
 7 import javax.persistence.GeneratedValue;
 8 import javax.persistence.Id;
 9 import javax.persistence.JoinColumn;
10 import javax.persistence.JoinTable;
11 import javax.persistence.ManyToMany;
12 import javax.persistence.Table;
13 
14 @Entity
15 @Table(name="t_teacher")
16 public class Teacher {
17     
18     private Integer id;
19     
20     private String name;
21     
22     private Set<Student> students = new HashSet<Student>();
23 
24     @Id
25     @GeneratedValue
26     public Integer getId() {
27         return id;
28     }
29 
30     public void setId(Integer id) {
31         this.id = id;
32     }
33 
34     public String getName() {
35         return name;
36     }
37 
38     public void setName(String name) {
39         this.name = name;
40     }
41 
42     @ManyToMany
43     @JoinTable(name="t_s",//中间表的表名
44         joinColumns={@JoinColumn(name="teacher_id")},//配置主键在中间表的配置
45         inverseJoinColumns={@JoinColumn(name="student_id")}//配置另一张多对多的表的主键在中间表的配置
46     )
47     public Set<Student> getStudents() {
48         return students;
49     }
50 
51     public void setStudents(Set<Student> students) {
52         this.students = students;
53     }
54 
55 }

　　　　　　Student:

 1 package com.bjsxt.hibernate;
 2 
 3 import java.util.HashSet;
 4 import java.util.Set;
 5 
 6 import javax.persistence.Entity;
 7 import javax.persistence.GeneratedValue;
 8 import javax.persistence.Id;
 9 import javax.persistence.ManyToMany;
10 import javax.persistence.Table;
11 
12 @Entity
13 @Table(name="t_student")
14 public class Student {
15     private Integer id;
16     
17     private String name;
18     
19     private Set<Teacher> teachers = new HashSet<Teacher>();
20     
21     @Id
22     @GeneratedValue
23     public Integer getId() {
24         return id;
25     }
26 
27     public void setId(Integer id) {
28         this.id = id;
29     }
30 
31     public String getName() {
32         return name;
33     }
34 
35     public void setName(String name) {
36         this.name = name;
37     }
38 
39     @ManyToMany(mappedBy="students")//以 Teacher 对应的表中，students属性的配置为准
40     public Set<Teacher> getTeachers() {
41         return teachers;
42     }
43 
44     public void setTeachers(Set<Teacher> teachers) {
45         this.teachers = teachers;
46     }
47 }

　　　　XML 配置：

　　　　　　Teacher.hbm.xml

 1 <?xml version="1.0"?>
 2 <!DOCTYPE hibernate-mapping PUBLIC
 3         "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
 4         "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
 5 
 6 <hibernate-mapping package="com.bjsxt.hibernate">
 7     <class name="Teacher" table="t_teacher">
 8         <id name="id" column="id">
 9             <generator class="native"/>
10         </id>
11         <property name="name" column="name" />
12         <set name="students" table="t_s">
13             <key column="teacher_id"></key><!-- 指定自己这张表在中间表的列名 -->
14             <many-to-many class="Student" column="student_id" /><!-- 指定多对多的那张表在中间表的列名 -->
15         </set>
16     </class>
17 </hibernate-mapping>

　　　　　　Student.hbm.xml

 1 <?xml version="1.0"?>
 2 <!DOCTYPE hibernate-mapping PUBLIC
 3         "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
 4         "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
 5 
 6 <hibernate-mapping package="com.bjsxt.hibernate">
 7     <class name="Student" table="t_student">
 8         <id name="id" column="id">
 9             <generator class="native"/>
10         </id>
11         <property name="name" column="name" />
12         <set name="teachers" table="t_s"><!-- 表名要一致 -->
13             <key column="student_id"></key><!-- 指定自己这张表在中间表的列名 -->
14             <many-to-many class="Teacher" column="teacher_id" /><!-- 指定多对多的那张表在中间表的列名 -->
15         </set>
16     </class>
17 </hibernate-mapping>

 

jar包链接: https://pan.baidu.com/s/1boWMlav 密码: 1mw3

代码链接: https://pan.baidu.com/s/1pLlqOB5 密码: v3c8

posted @ 2017-04-21 11:29  流年如水烟雨随风  阅读(330)  评论(0)  编辑  收藏  举报