SpringDataJPA笔记(15)--Inheritance注解详解之JOINED

SpringDataJPA笔记(15)–Inheritance注解详解之JOINED

在JPA中使用映射注解Inheritance，有一种策略是JOINED

JOINED – 每个类分别生成一张单独的表，但是每张表只有自己的属性，没有父类的属性，通过外键关联的形式使两张表关联起来

还是简单写个demo测试一下

先写三个实体类

@Data
@Table(name = "inheritance_joined_tb")
@Entity
@Inheritance(strategy = InheritanceType.JOINED)
public class InheritanceJoinedEntity implements Serializable {
    private static final long serialVersionUID = 8139674112977338603L;

    @Id
    private Long id;

    @Column(name = "joined_name")
    private String joinedName;
}

@Data
@Entity
@EqualsAndHashCode(callSuper = true)
@Table(name = "inheritance_joined_one_tb")
public class InheritanceJoinedOneEntity extends InheritanceJoinedEntity {

    private static final long serialVersionUID = 9042160117012026124L;

    @Column(name = "joined_one")
    private String joinedOne;
}

@Data
@Entity
@EqualsAndHashCode(callSuper = true)
@Table(name = "inheritance_joined_two_tb")
public class InheritanceJoinedTwoEntity extends InheritanceJoinedEntity {

    private static final long serialVersionUID = 9042160117012026124L;

    @Column(name = "joined_two")
    private String joinedTwo;
}

然后是三个repository接口类

public interface InheritanceJoinedRepository extends JpaRepository, JpaSpecificationExecutor, Serializable {
}

public interface InheritanceJoinedOneRepository extends JpaRepository, JpaSpecificationExecutor, Serializable {
}

public interface InheritanceJoinedTwoRepository extends JpaRepository, JpaSpecificationExecutor, Serializable {
}

然后写controller类用于测试

@Autowired
    private InheritanceJoinedRepository inheritanceJoinedRepository;

    @Autowired
    private InheritanceJoinedOneRepository inheritanceJoinedOneRepository;

    @Autowired
    private InheritanceJoinedTwoRepository inheritanceJoinedTwoRepository;

    @PostMapping("/single")
    public InheritanceJoinedEntity single(@RequestBody InheritanceJoinedEntity inheritanceJoinedEntity) {
        return inheritanceJoinedRepository.save(inheritanceJoinedEntity);
    }

    @PostMapping("/joined/one")
    public InheritanceJoinedOneEntity joined(@RequestBody InheritanceJoinedOneEntity inheritanceJoinedEntity) {
        return inheritanceJoinedOneRepository.save(inheritanceJoinedEntity);
    }

    @PostMapping("/joined/two")
    public InheritanceJoinedTwoEntity joined(@RequestBody InheritanceJoinedTwoEntity inheritanceJoinedEntity) {
        return inheritanceJoinedTwoRepository.save(inheritanceJoinedEntity);
    }

    @GetMapping("/joined")
    public List joined() {
        return inheritanceJoinedRepository.findAll();
    }

    @GetMapping("/joined/one")
    public List joinedOne() {
        return inheritanceJoinedOneRepository.findAll();
    }

    @GetMapping("/joined/two")
    public List joinedTwo() {
        return inheritanceJoinedTwoRepository.findAll();
    }

启动程序，查看数据库，有三张表

分别通过三个接口写入数据，再查看数据库数据

通过接口查询数据的结果

欢迎关注微信交流