Hibernate（五）注解开发多对多

举例：老师和学生

teacher实体

package cn.hibernate.annotationmapping;

import org.hibernate.annotations.GenericGenerator;

import javax.persistence.*;
import java.util.HashSet;
import java.util.Set;

/**
 * Created by 17921 on 2017/12/31.
 */
@Entity//将该类声明为一个实体
@Table(name = "Teacher")//指定表的名称
@GenericGenerator(name = "teid",strategy = "native")//创建主键生成策略
public class Teacher {
    @Id//指定为表的ID
    @GeneratedValue(generator = "teid")//指定主键生成策略
    @Column(name = "tid")//对应数据表的类名
    private Integer tid;
    @Column(name = "tname")
    private String tname;

    @ManyToMany//多对多
    //中间表    中间表的名称        本实体对应中间表的列                      另一个实体对应中间表的列
    @JoinTable(name = "RStuTe",joinColumns={@JoinColumn(name = "tid")},inverseJoinColumns = {@JoinColumn(name = "sid")})
    private Set<Students> students=new HashSet<Students>();


    //省略getset方法
}

　　Student实体

package cn.hibernate.annotationmapping;

import org.hibernate.annotations.*;
import org.hibernate.annotations.CascadeType;

import javax.naming.Name;
import javax.persistence.*;
import javax.persistence.Entity;
import javax.persistence.Table;
import java.util.HashSet;
import java.util.Set;

/**
 * Created by 17921 on 2017/12/31.
 */
@Entity//将该类声明为一个实体
@Table(name = "Students")//指定表的名称
@GenericGenerator(name = "stuid",strategy = "native")//创建主键生成策略
public class Students {
    @Id//指定为表的ID
    @GeneratedValue(generator = "stuid")//指定主键生成策略
    @Column(name = "sid")//对应数据表的类名
    private Integer sid;
    @Column(name = "sname")
    private String sname;

    @ManyToMany()//多对多
    @Cascade(value = {CascadeType.SAVE_UPDATE})//级联
    //中间表    中间表的名称        本实体对应中间表的列                      另一个实体对应中间表的列
    @JoinTable(name = "RStuTe",joinColumns = {@JoinColumn(name = "sid")},inverseJoinColumns = {@JoinColumn(name = "tid")})
    private Set<Teacher> teachers=new HashSet<Teacher>();


   省略getset方法
}

　　单测

 @Test
    public void sel(){
        Teacher teacher1=new Teacher();
        teacher1.setTname("老袁");
        Teacher teacher2=new Teacher();
        teacher2.setTname("付老师");
        Teacher teacher3=new Teacher();
        teacher3.setTname("彪哥");


        Students students1=new Students();
        students1.setSname("老黑");
        Students students2=new Students();
        students2.setSname("小芮");
        Students students3=new Students();
        students3.setSname("城余");


        students1.getTeachers().add(teacher1);
        students1.getTeachers().add(teacher2);
        students2.getTeachers().add(teacher1);
        students2.getTeachers().add(teacher2);
        students3.getTeachers().add(teacher1);
        students3.getTeachers().add(teacher3);

        Session session = HibernateUtil.getSession();
        session.save(students1);
        session.save(students2);
        session.save(students3);

        HibernateUtil.closeSession();
        System.out.println("add ok!");
    }

　　结果

student表

teacher表

中间表