Hibernate annotation 多对多双向关联(很少用)

原创

hongmin118 2023-02-17 09:06:11 ©著作权

文章标签 java hibernate xml 文章分类 Python 后端开发

©著作权归作者所有：来自51CTO博客作者hongmin118的原创作品，请联系作者获取转载授权，否则将追究法律责任

双向关联在认为的主表上用到 @JoinTable

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.ManyToMany;

@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(mappedBy="students")//students 是 teacher类里的student属性
  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;
  }
  
}