JPA 多对多查询

person 实体

package com.lyr.easymybatis.pojo.po;

import lombok.Data;
import lombok.experimental.Accessors;
import org.hibernate.annotations.DynamicInsert;
import org.hibernate.annotations.DynamicUpdate;
import org.springframework.data.jpa.domain.support.AuditingEntityListener;

import javax.persistence.*;
import java.util.ArrayList;
import java.util.List;

/**
 * @Author lyr
 * @create 2020/12/15 14:02
 */
@Entity
@Data
@Accessors(chain = true)
@DynamicInsert
@DynamicUpdate
@EntityListeners(AuditingEntityListener.class)
public class Person {
    
    

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long personId;

    private String name;

    // @Column(nullable = false)
    // private Integer sex;

    @ManyToMany(fetch = FetchType.EAGER)
    @JoinTable(name = "t_person_role")
    // @JoinTable(name = "person_role",
    //         inverseJoinColumns= {@JoinColumn(name = "person_id", referencedColumnName = "person_id")},
    //         joinColumns = {@JoinColumn(name = "role_id", referencedColumnName = "role_id")})
    private List<Role> roles ;

}

role 实体

package com.lyr.easymybatis.pojo.po;

import lombok.Data;
import lombok.experimental.Accessors;
import org.hibernate.annotations.DynamicInsert;
import org.hibernate.annotations.DynamicUpdate;
import org.springframework.data.jpa.domain.support.AuditingEntityListener;

import javax.persistence.*;
import java.util.List;

/**
 * @Author lyr
 * @create 2020/12/15 14:03
 */
@Entity
@Data
@Accessors(chain = true)
@DynamicInsert
@DynamicUpdate
@EntityListeners(AuditingEntityListener.class)
public class Role {
    
    
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long roleId;

    /**
     * 数据库唯一
     */
    @Column(nullable = false, unique = true)
    private String name;




}

测试代码：

    @Resource
    private RoleRepository roleRepository;
    @Resource
    private PersonRepository personRepository;
    @Test
    void printRoless() {
    
    
        Role role = new Role().setName("老师");
        Role role1 = new Role().setName("学生");
        roleRepository.saveAll(Arrays.asList(role,role1));
    }

    @Test
    @Transactional
    @Rollback(false)
    void insert11() {
    
    
        Role r = new Role().setName("学生");

        personRepository.save(new Person().setName("东哥1144").setRoles(Arrays.asList(r.setRoleId(4L) )));
        // personRepository.findAll()
        //         .stream()
        //         .forEach(System.out::println);
    }


    @Test
    void printPersonALL() {
    
    
        personRepository
                .findAll()
                .forEach(l -> System.out.println(l));
    }


    @Test
    void ll() {
    
    
        roleRepository
                .findAll()
                .forEach(l -> System.out.println(l));
    }

Hibernate:
select
person0_.person_id as person_i1_1_,
person0_.name as name2_1_
from
person person0_
Hibernate:
select
roles0_.person_person_id as person_p1_3_0_,
roles0_.roles_role_id as roles_ro2_3_0_,
role1_.role_id as role_id1_2_1_,
role1_.name as name2_2_1_
from
t_person_role roles0_
inner join
role role1_
on roles0_.roles_role_id=role1_.role_id
where
roles0_.person_person_id=?
Person(personId=6, name=东哥1144, roles=[Role(roleId=4, name=学生)])