多对多的单向关联

一个老师（Teacher）教多个学生（Student），一个学生（Student）可以有多名老师（Teacher），这就是一对一的关系，下面以这个例子为例进行配置：

　　Annotataion 配置：

　　　　Teacher:

　　　　　　

package com.bjsxt.hibernate;

import java.util.HashSet;
import java.util.Set;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.Table;

@Entity
@Table(name="t_teacher")
public class Teacher {
    
    private Integer id;
    
    private String name;
    
    private Set<Student> students = new HashSet<Student>();

    @Id
    @GeneratedValue
    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;
    }

    @ManyToMany
    @JoinTable(name="t_s",
        joinColumns={@JoinColumn(name="teacher_id")},
        inverseJoinColumns={@JoinColumn(name="student_id")}
    )
    public Set<Student> getStudents() {
        return students;
    }

    public void setStudents(Set<Student> students) {
        this.students = students;
    }

}

　　　　　　Student:　　　　　　　　

package com.bjsxt.hibernate;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name="t_student")
public class Student {
    private Integer id;
    
    private String name;
    
    @Id
    @GeneratedValue
    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;
    }
}

　　XML 配置：

　　　　　　Teacher.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="com.bjsxt.hibernate">
    <class name="Teacher" table="t_teacher">
        <id name="id" column="id">
            <generator class="native"/>
        </id>
        <property name="name" column="name" />
        <set name="students" table="t_s">
            <key column="teacher_id"></key><!-- 指定自己这张表在中间表的列名 -->
            <many-to-many class="Student" column="student_id" /><!-- 指定多对多的那张表在中间表的列名 -->
        </set>
    </class>
</hibernate-mapping>

　　　　　　Student.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping package="com.bjsxt.hibernate">
    <class name="Student" table="t_student">
        <id name="id" column="id">
            <generator class="native"/>
        </id>
        <property name="name" column="name" />
    </class>
</hibernate-mapping>

上面两种方式，生成SQL的结果一样，生成顺序：

jar链接: https://pan.baidu.com/s/1eSKKZ8Q 密码: puad

代码链接: https://pan.baidu.com/s/1bpxk8H5 密码: e7ku