Hibernate单向多对多关联。如:一个学生对应多门课程，一门课程也对应多名学生。本例单向关联，只考虑学生到课程的一对多关联。
1、概述
a.实体类
public class Student{
......
private Set<Course> courses;
......
}
public class Course{
......
}
b.数据库表
Student与Course各对应一张数据库表，再建一张关联表student_course (studentid,courseid)，保存多对多关联。其中，student_course表的主键为studentid与courseid的联合。
c.配置文件
Student.hbm.xml:
......
<set name="courses" table="student_course" cascade="all">
<key column="studentid" />
<many-to-many column="courseid" class="wintys.hibernate.manytomany.Course"/>
</set>
......
Course.hbm.xml:
......
2、实体类:
Student.java:
package wintys.hibernate.manytomany;
import java.util.Set;
/**
* @version 2009-06-19
* @author Winty (wintys@gmail.com)
*
*/
public class Student {
private Integer id;
private String name;
private Set<Course> courses;
public Student(){
}
public Student(String name){
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 Set<Course> getCourses() {
return courses;
}
public void setCourses(Set<Course> courses) {
this.courses = courses;
}
}
|
Course.java:
package wintys.hibernate.manytomany;
import java.util.Set;
/**
* @version 2009-06-19
* @author Winty (wintys@gmail.com)
*
*/
public class Course {
private Integer id;
private String name;
public Course(){
}
public Course(String name){
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;
}
}
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