Why I am receiving empty array?-CodePudding

I am doing a project in Spring and Postgres. I am getting this empty column when I try to call a request with Postman. As you can see, it returns everything except ingredient column.

{
        "recept_id": 8,
        "recept_name": "conceptual",
        "nation_id": 1,
        "type_id": 1,
        "isvegan": true,
        "isvegetarian": true,
        "photo": null,
        "video": null,
        "ingredient": [],
        "level_id": 5,
        "recept_view": 1,
        "company_id": 4,
        "ratinglvl": 5
    }

However, in Postgres, this column has data ({1,2,3}). The data type of the ingredient column is an integer[] in Postgres. I inserted data to ingredient to Postgres manually.

While in Spring, I am using a simple CRUDrepository.

Entity:

   @Data
    @NoArgsConstructor
    @AllArgsConstructor
    @Entity
    @Table(name = "recept")
    public class Recept {
        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        private long recept_id;
        @Column
        private String recept_name;
        private long nation_id;
        private long type_id;
        private boolean isvegan;
        private boolean isvegetarian;
        private File photo;
        private File video;
        @ElementCollection(targetClass=Long.class)
        private List<Long> ingredient;
        private short level_id;
        private long recept_view;
        private long company_id;
        private short ratinglvl;
    }

Controller:

@RestController
public class ReceptController {
    private final ReceptService receptService;

    public ReceptController(ReceptService receptService) {
        this.receptService = receptService;
    }
    @RequestMapping(value="/recept",method= RequestMethod.GET, headers = "Accept=application/json")
    public ResponseEntity<?> getAll() {
        return ResponseEntity.ok(receptService.getAll());
    }

Repository:

public interface ReceptRepository extends CrudRepository<Recept, Long> {}

Service:

@Service
public class ReceptService {
    private final ReceptRepository receptRepository;
    private final IngredientRepository ingredientRepository;


    public ReceptService(ReceptRepository receptRepository, IngredientRepository ingredientRepository) {
        this.receptRepository = receptRepository;
        this.ingredientRepository = ingredientRepository;
    }

    public List<Recept> getAll(){

        return (List<Recept>)receptRepository.findAll();
    }

Don't know why it doesn't return it.

CodePudding user response：

@ElementCollection is meant to collect the values of a column in a related table -not to denote a PostgreSQL array type.

In order to use Postgresql arrays, you need to define a custom type. Thankfully the hibernate-types library already provides a ListArrayType out of the box. This will allow you to define your entity like:


    @Data
    @NoArgsConstructor
    @AllArgsConstructor
    @Entity
    @TypeDef(
      name = "list-array"
      typeClass = ListArrayType.class
    )
    @Table(name = "recept")
    public class Recept {
        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        private long recept_id;
        @Column
        private String recept_name;
        private long nation_id;
        private long type_id;
        private boolean isvegan;
        private boolean isvegetarian;
        private File photo;
        private File video;
        @ElementCollection(targetClass=Long.class)
        @Type(type = "list-array)
        @Column( 
           name = "ingredient",
           columnDefinition = "integer[]"
        )
        private List<Long> ingredient;
        private short level_id;
        private long recept_view;
        private long company_id;
        private short ratinglvl;
    }