Hibernate annotation 多对多单向关联

 

package com.hibernate.entity;

import java.io.Serializable;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;

@Entity
public class Student implements Serializable {

  /**
   * 
   */
  private static final long serialVersionUID = 3543286868313801941L;
  
  private int id;
  
  private String name;
  
//  private Set<Teacher> teachers = new HashSet<Teacher>();

  
  @Id
  @GeneratedValue
  public int getId() {
    return id;
  }

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

  public String getName() {
    return name;
  }

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

//  @ManyToMany
//  public Set<Teacher> getTeachers() {
//    return teachers;
//  }
//
//  public void setTeachers(Set<Teacher> teachers) {
//    this.teachers = teachers;
//  }
  
  
  
  
}

 

 

package com.hibernate.entity;

import java.io.Serializable;
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;

@Entity
public class Teacher implements Serializable {

  /**
   * 
   */
  private static final long serialVersionUID = 3543286868313801941L;
  
  private int id;
  
  private String name;
  
  private Set<Student> students = new HashSet<Student>();

  
  @Id
  @GeneratedValue
  public int getId() {
    return id;
  }

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

  public String getName() {
    return name;
  }

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

  
  @ManyToMany
  @JoinTable(
          name="s_t",
          joinColumns=
              @JoinColumn(name="teacherid", referencedColumnName="id"),//当前表里的id
          inverseJoinColumns=
              @JoinColumn(name="studentid", referencedColumnName="id")//与此相对应的表里的id
          )
  public Set<Student> getStudents() {
    return students;
  }

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

 hibernate.cfg.xml和ORMappingTest与之前一样，拷过来就可以使用

当然，.xml中要加

<mapping class="com.hibernate.entity.Teacher" />
<mapping class="com.hibernate.entity.Student" />