java - 在所有嵌套实体中选择几个 : SPRING JPA

Question

我有一个像下面这样的场景。
让我们说 EntityA具有三个嵌套实体 EntityB, EntityC, EntityD .以及所有 EntityB, EntityC, EntityD里面有几个嵌套的实体。
但是在选择EntityA时它选择嵌套实体的整个树。而我想获取特定的分支。只能说 EntityA, EntityB以及 EntityB 的所有子实体被取走EntityC和 EntityD那时我不知道该怎么做。随着 spring jpa 将所有嵌套对象带回给我。
我正在使用以下集合映射。

 @Entity
 @Table(name = "customer_party_mapping")
 @Data
 public class CustomerPartyMappingEntity {
    
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private Integer id;
    
    @Column(name = "customer_id")
    private Integer custmerId;
    
    @Column(name = "orgtype_id")
    private Integer orgTypeId;
    
    @OneToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL )
    @JoinColumn(name = "customer_party_mapping_id")
    @Fetch(value = FetchMode.SUBSELECT)
    private List<CustomerPartyBookingLocationEntity> customerPartyBookingLocation=new ArrayList<CustomerPartyBookingLocationEntity>();
    
    @OneToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL )
    @JoinColumn(name = "customer_party_mapping_id")
    @Fetch(value = FetchMode.SUBSELECT)
    private List<CustomerPartyFieldMappingEntity> customerPartyFieldMappingEntity=new ArrayList<CustomerPartyFieldMappingEntity>();

    @OneToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL )
    @JoinColumn(name = "customer_party_mapping_id",referencedColumnName="id")
    @Fetch(value = FetchMode.SUBSELECT)
    private List<CustomerPartyOtherDocumentEntity> otherDocumentsList=new 
    ArrayList<>();
    
    @OneToOne( cascade={ CascadeType.PERSIST, CascadeType.MERGE })
    @JoinColumn(name = "customer_name_screening_id", referencedColumnName="id") 
    private CustomerNameScreeningEntity customerNameScreeningEntity;
        
    @OneToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL )
    @JoinColumn(name = "customer_party_mapping_id")
    @Fetch(value = FetchMode.SUBSELECT)
    private List<CustomerDocInfoTrackingEntity> customerDocInfoTrackingList=new 
    ArrayList<CustomerDocInfoTrackingEntity>();
}

我在打电话

List<CustomerPartyMappingEntity> customerPartyMappingEntityList = customerPartyMappingRepository.findByCustmerId(customerid);

它获取所有嵌套的实体映射列表，而我只需要 CustomerPartyMappingEntity及其列表 customerPartyFieldMappingEntity嵌套对象。
任何帮助将不胜感激。

Answer 1

第一次使用 FetchType.LAZY对于嵌套实体。
那么你可以使用@EntityGraph使用 . 按名称获取嵌套实体，并使用其名称获取嵌套实体在存储库中。您过去只在 attributePaths 中指定嵌套属性喜欢

@EntityGraph(attributePaths = {"customerPartyBookingLocation"})

以及 customerPartyBookingLocation 的嵌套属性喜欢

@EntityGraph(attributePaths = {"customerPartyFieldMappingEntity.subField"})

例子:

@EntityGraph(attributePaths = {"customerPartyBookingLocation", "customerPartyFieldMappingEntity.subField"})
List<CustomerPartyMappingEntity> findByCustmerId(Integer customerid);

注意:您不能将 @EntityGraph 与 @Query 注释一起使用