Hibernate 映射關係 ---Many2Many 單向關聯

一個學生可以有多個老師，一個老師也可以有多個學生，所以老師和學生之間的關係就是多對多的關係，這樣就需要建立一箇中間的關聯表來存儲關聯信息。

package com.pojo;
public class Student implements java.io.Serializable {
    private Long id;
    private String name;
    private Long age;
    private String sex;
    public Student() {
    }
    public Long getId() {
        return this.id;
    }
    public void setId(Long id) {
        this.id = id;
    }
    public String getName() {
        return this.name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Long getAge() {
        return this.age;
    }
    public void setAge(Long age) {
        this.age = age;
    }
    public String getSex() {
        return this.sex;
    }
    public void setSex(String sex) {
        this.sex = sex;
    }
}

 

package com.pojo;
import java.util.HashSet;
import java.util.Set;
public class Teacher implements java.io.Serializable {
    private static final long serialVersionUID = -7640561034271065452L;
    private Long id;
    private String name;
    private String sourcename;
    //多對多單向關聯
    private Set<Student> students = new HashSet<Student>() ;
    public Teacher() {
    }
    public Long getId() {
        return this.id;
    }
    public void setId(Long id) {
        this.id = id;
    }
    public String getName() {
        return this.name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getSourcename() {
        return this.sourcename;
    }
    public void setSourcename(String sourcename) {
        this.sourcename = sourcename;
    }
    public Set<Student> getStudents() {
        return students;
    }
    public void setStudents(Set<Student> students) {
        this.students = students;
    }
}

 

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!--
    Mapping file autogenerated by MyEclipse Persistence Tools
-->
<hibernate-mapping>
    <class name="com.pojo.Teacher" table="TEACHER" schema="ZM">
        <id name="id" type="java.lang.Long">
            <column name="ID" precision="4" scale="0" />
            <generator class="increment" />
        </id>
        <property name="name" type="java.lang.String">
            <column name="NAME" length="100" />
        </property>
        <property name="sourcename" type="java.lang.String">
            <column name="SOURCENAME" length="100" />
        </property>
        <!--
            多對多單向關聯,table標識關聯表，key裏面column屬性代表該類（Teacher）在關聯表裏面的鍵是teacher_id
            many-to-many 裏面class屬性是set裏面的類型，後面的column是指該類在關聯表裏面的外鍵
            outer-join="true" 外連接
            cascade="save-update" 級聯操作
         -->
        <set name="students" table="stutea" outer-join="true" cascade="save—update">
         <key column="teacher_id"></key>
         <many-to-many class="com.pojo.Student" column="student_id"/>
        </set>

    </class>
</hibernate-mapping>

本文出自：http://blog.csdn.net/gaowenming/article/details/5020902