How can I retrieve the list of object associated as field into an entity class?

问题

when i fine a Customer by any of his fields, everything goes well, i get the JSON with the global object returned.

i am writing a code to fine a Customer By his lastName. The Customer Entity has and object in wich the field lastName is declared. So i want my Endpoint to return the Customer Global Object as in the first case.

I have into my postman Status 200 OK, but with and empty body. Any solution ? THANKS

here is a sample. The lastName field is declared both into the prefBillAddressUid and prefShipAddressUid objects

@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

 }

My repository

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

Implementation of Service

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

here is my ressource

    @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)
            );
}

customerAddress Class

@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

}

回答1:

Firstly, You cannot return CustomerAddress from CustomerRepository.
Some of the alternatives are

To retrieve CustomerAddress based on last name from CustomerRepository, you can do something like this

Customer findByPrefBillAddressUid_LastName(String lastName);

spring-data will formulate the query, You don't need @Query. But notice that the return type if Customer and not CustomerAddress. So you will get a customer object with the correct customerAddress.

If you want to return CustomerAddress, then you need to create CustomerAddressRepository and write a method like this

CustomerAddress findByLastName(String lastName);

Use Projections Create a interface like this

 interface CustomerShort {
    CustomerAddress getPrefBillAddressUid();
}

and then your CustomerRepository needs to have a method like this

interface CustomerRepository extends CRUDRepository<Customer, UUID> {

  Collection<CustomerShort> findByPrefBillAddressUid_LastName(String lastName);
}

来源：https://stackoverflow.com/questions/48426102/how-can-i-retrieve-the-list-of-object-associated-as-field-into-an-entity-class

标签

hibernate

spring-mvc

spring-data-jpa