Hibernate_映射_关联关系_多对多映射1

引用自已主键的那个
  3,引用关联对象的那个外键            3,引用关联对象的那个外键            
  4,关联的实体类型              4,关联的实体类型

学生映射文件

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- 导入包 -->
<hibernate-mapping package="cn.itcast.g_hbm_manyToMany">
  <!-- 类名 -->
  <class name="Student" table="t_student">
    <id name="id" type="integer" column="id">
      <generator class="native" />
    </id>
    <property name="name" type="string" column="name" />

    <!-- teachers属性,Set集合。
      表达的是本类与Teacher的多对多的关联关系 
      
      table属性：中间表(集合表)
      key子元素：集合外键 (引用当前表主键的那个外键)
    -->
    <set name="teachers" table="t_teacher_student">
      <key column="studentId"></key>
      <many-to-many class="Teacher" column="teacherId"></many-to-many>
    </set>
  </class>
</hibernate-mapping>

老师映射文件

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- 导入包 -->
<hibernate-mapping package="cn.itcast.g_hbm_manyToMany">
  <!-- 类名 -->
  <class name="Teacher" table="t_teacher">
    <id name="id" type="integer" column="id">
      <generator class="native" />
    </id>
    <property name="name" type="string" column="name" />
    
    <!-- students属性,Set集合。
      表达的是本类与Student的多对多的关联关系 
      
      table属性：中间表(集合表)
      key子元素：集合外键 (引用当前表主键的那个外键)
    -->
    <set name="students" table="t_teacher_student">
      <key column="teacherId"></key>
      <many-to-many class="Student" column="studentId"></many-to-many>
    </set>
  </class>
</hibernate-mapping>

学生实体类

package cn.itcast.g_hbm_manyToMany;

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

/**
 * 学生
 * 
 * @author 风清杨
 * @version V1.0
 */
public class Student {
  private Long id;
  private String name;
  private Set<Teacher> teachers = new HashSet<Teacher>();// 关联得老师位

  public Long getId() {
    return id;
  }

  public void setId(Long id) {
    this.id = id;
  }

  public String getName() {
    return name;
  }

  public void setName(String name) {
    this.name = name;
  }

  public Set<Teacher> getTeachers() {
    return teachers;
  }

  public void setTeachers(Set<Teacher> teachers) {
    this.teachers = teachers;
  }

  @Override
  public String toString() {
    return "Student [id=" + id + ", name=" + name + "]";
  }

}

老师实体类

package cn.itcast.g_hbm_manyToMany;

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

/**
 * 老师
 * 
 * @author 风清杨
 * @version V1.0
 */
public class Teacher {
  private Long id;
  private String name;
  private Set<Student> students = new HashSet<Student>();// 关联的学生们

  public Long getId() {
    return id;
  }

  public void setId(Long id) {
    this.id = id;
  }

  public String getName() {
    return name;
  }

  public void setName(String name) {
    this.name = name;
  }

  public Set<Student> getStudents() {
    return students;
  }

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

  @Override
  public String toString() {
    return "Teacher [id=" + id + ", name=" + name + "]";
  }

}

组合映射文件

private static SessionFactory sessionFactory = new Configuration()//
      .configure()//
      .addClass(Student.class)// 添加Hibernate实体类(加载对应的映射文件)
      .addClass(Teacher.class)// 添加Hibernate实体类(加载对应的映射文件)
      .buildSessionFactory();