SpringDataJPA筆記(15)--Inheritance註解詳解之JOINED

原創

yingziisme

2020-04-20 18:16

SpringDataJPA筆記(15)–Inheritance註解詳解之JOINED

在JPA中使用映射註解Inheritance，有一種策略是JOINED

JOINED – 每個類分別生成一張單獨的表，但是每張表只有自己的屬性，沒有父類的屬性，通過外鍵關聯的形式使兩張表關聯起來

還是簡單寫個demo測試一下

先寫三個實體類

@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;
}

然後是三個repository接口類

public interface InheritanceJoinedRepository extends JpaRepository<InheritanceJoinedEntity, Long>, JpaSpecificationExecutor<InheritanceJoinedEntity>, Serializable {
}

public interface InheritanceJoinedOneRepository extends JpaRepository<InheritanceJoinedOneEntity, Long>, JpaSpecificationExecutor<InheritanceJoinedOneEntity>, Serializable {
}

public interface InheritanceJoinedTwoRepository extends JpaRepository<InheritanceJoinedTwoEntity, Long>, JpaSpecificationExecutor<InheritanceJoinedTwoEntity>, Serializable {
}

然後寫controller類用於測試

@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<InheritanceJoinedEntity> joined() {
        return inheritanceJoinedRepository.findAll();
    }

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

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

啓動程序，查看數據庫，有三張表