如何将与字段关联的对象列表检索到实体类中？

当我通过任何字段找到客户时，一切都很顺利，我得到了带有返回的全局对象的 JSON。

我正在编写代码来查找Customer由于他们lastName。客户实体有一个对象，其中的字段lastName被宣布。因此，我希望我的端点像第一种情况一样返回客户全局对象。

我已经进入我的邮递员状态 200 OK，但身体空了。有什么解决办法吗？谢谢

这是一个示例。 LastName 字段在 prefBillAddressUid 和 prefShipAddressUid 对象中声明

@Entity
@Table(name = "tcustomer")
public class Customer implements Serializable{

private static final long serialVersionUID = 1L;

@Id
@SequenceGenerator(name = "pk_sequence",sequenceName = "sequence_tcustomer",initialValue = 1000, allocationSize = 100)
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "pk_sequence")
private Long uidpk;

@Column(name = "user_id", nullable=false)
private String userId;

@OneToOne(cascade = CascadeType.ALL)
@JoinColumn(name = "pref_bill_address_uid")
private CustomerAddress prefBillAddressUid;

@OneToOne(cascade = CascadeType.ALL)
@JoinColumn(name = "pref_ship_address_uid")
private CustomerAddress prefShipAddressUid;

...

//getters and setters 
//constructors

 }

我的存储库

  @Query(value = "SELECT c FROM CustomerAddress c WHERE c.lastName = :lastName")
  CustomerAddress findByLastName(   @Param("lastName") String lastName);

服务实施

    @Override
    public CustomerAddressDto findByLastName(String lastName) {
    CustomerAddress result = customerRepository.findByLastName(lastName);
    return customerAddressMapper.customerAddressToCustomerAddressDto(result);
}

这是我的资源

    @GetMapping(SEARCH_CUSTOMER_LAST_NAME_ENDPOINT)
@ResponseStatus(value = HttpStatus.OK)
@ApiResponses(value = {
        @ApiResponse(code = 200,  message = "OK", response = CustomerAddressDto.class),
        @ApiResponse(code = 500, message = "Unexpected error", response = CustomerAddressDto.class)
})
@Timed
public  ResponseEntity getCustomerByLastName ( @PathVariable String lastName) throws URISyntaxException {
    if (log.isDebugEnabled()){
        log.debug("[CustomerResource] GET {} : Retrieving Customer ({})", SEARCH_CUSTOMER_LAST_NAME_ENDPOINT, lastName);
    }

    CustomerAddressDto customerAddressDto = customerService.findByLastName(lastName);

    return Optional.ofNullable(customerAddressDto)
            .map(result->{
                if (log.isDebugEnabled()){
                    log.debug("[CustomerResource] Customer ({}) retrieved", result.getLastName());
                }
                return new ResponseEntity<>(HttpStatus.OK);
            })
            .orElse(new ResponseEntity(new ResponseError(HttpStatus.NOT_FOUND.getReasonPhrase(),
                    "The Customer with lastName " + lastName + " does not exists"), null,HttpStatus.NOT_FOUND)
            );
}

客户地址类

@Entity
@Table(name="taddress")
public class CustomerAddress implements Serializable{

private static final long serialVersionUID = 1L;

@Id
@SequenceGenerator(name = "pk_sequence",sequenceName = "sequence_taddress",initialValue = 1000, allocationSize = 100)
@GeneratedValue(strategy = GenerationType.SEQUENCE,generator = "pk_sequence")
private Long uidpk;

@Column(name = "last_name")
private String lastName;

@Column(name = "first_name")
private String firstName;

@Column(name = "phone_number")
private String phoneNumber;

@Column(name= "fax_number")
private String faxNumber;

@Column(name = "street_1")
private String street1;

@Column(name= "street_2")
private String street2;

@Column(name= "city")
private String city;

@Column(name= "sub_country")
private String subCountry;

@Column(name= "zip_postal_code")
private String zipPostalCode;

@Column(name= "country")
private String country;

@Column(name = "commercial")
private Boolean commercial;

@Column(name = "guid", nullable=false)
private String guid;

@Column(name = "customer_uid")
private Long customerUid;

@Column(name= "type")
private String type;

@Column(name = "organization")
private String organization;

...
//getters ans setters
}

首先，您无法从 CustomerRepository 返回 CustomerAddress。
一些替代方案是

1. 根据姓氏检索 CustomerAddressCustomerRepository，你可以这样做

   Customer findByPrefBillAddressUid_LastName(String lastName);

spring-data 会制定查询，你不需要@Query。但请注意，返回类型如果Customer并不是CustomerAddress。因此，您将获得具有正确 customerAddress 的客户对象。

2. 如果你想返回CustomerAddress，那么你需要创建CustomerAddressRepository并编写这样的方法

   CustomerAddress findByLastName(String lastName);

3. Use 预测 https://docs.spring.io/spring-data/jpa/docs/current/reference/html/#projections创建一个这样的界面

    interface CustomerShort {
       CustomerAddress getPrefBillAddressUid();
   }
   

   然后你的 CustomerRepository 需要有这样的方法

   interface CustomerRepository extends CRUDRepository<Customer, UUID> {
   
     Collection<CustomerShort> findByPrefBillAddressUid_LastName(String lastName);
   }