Spring MVC - 将实体放在一起的最佳位置是 Rest API

Question

设置父实体的最佳位置在哪里？换句话说，将实体放在一起的最佳位置在哪里？

在控制器中，找到父实体并设置为子实体然后保存？

@RestController
public class SomeController{

    @Autowired
    private SomeService someService;

    @PostMapping("/parents/{parentEntityId}/childs")
    public ResponseEntity<Void> save(@PathVariable("parentEntityId") Long parentEntityId, @RequestBody ChildDto childDto) {
        Optional<ParentEntity> parentEntity = someService.findParentById(parentEntityId);
        if (parentEntity.isPresent()) {
            ChildEntity childEntity = childDtoMapper.fromDto(childDto);
            childEntity.setParent(parentEntity.get());
            someService.saveChild(childEntity);
            return ResponseEntity.created(...).build();
        }
        throw new EntityNotFoundException("Parent entity not found!");
    }
}

或

在控制器中，将 dto 映射到实体，然后将实体和父实体 id 发送到服务，然后通过 id 找到父实体并设置为子实体并保存？

@RestController
public class SomeController {

    @Autowired
    private SomeService someService;

    @PostMapping("/parents/{parentEntityId}/childs")
    public ResponseEntity<Void> save(@PathVariable("parentEntityId") Long parentEntityId, @RequestBody ChildDto childDto) {
            ChildEntity childEntity = childDtoMapper.fromDto(childDto);
            someService.saveChild(parentEntityId, childEntity);
            return ResponseEntity.created(...).build();
    }
}

public class SomeServiceImpl {

    @Autowired
    private ParentEntityRepository parentEntityRepository;

    @Autowired
    private ChildEntityRepository childEntityRepository;

    public ChildEntity saveChild(final long parentEntityId, final ChildEntity childEntity){
        Optional<ParentEntity> parentEntity = parentEntityRepository.findById(parentEntityId);
        if (parentEntity.isPresent()) {
            childEntity.setParent(parentEntity.get());
            childEntityRepository.save(childEntity);
            return childEntity;
        }
        throw new EntityNotFoundException("Parent entity not found!");
    }
}

Answer 1

我会选择第二个选项并进行以下修改：

@RestController
public class SomeController {

    @Autowired
    private SomeService someService;

    @PostMapping("/parents/{parentEntityId}/childs")
    public ResponseEntity<Void> save(@PathVariable("parentEntityId") Long parentEntityId, @RequestBody ChildDto childDto) {
            someService.saveChild(parentEntityId, childDto);
            return ResponseEntity.created(...).build();
    }
}

public class SomeServiceImpl {

    @Autowired
    private ParentEntityRepository parentEntityRepository;

    @Autowired
    private ChildEntityRepository childEntityRepository;

    public ChildEntity saveChild(final long parentEntityId, final ChildDto childDto){
        ChildEntity childEntity = childDtoMapper.fromDto(childDto);
        Optional<ParentEntity> parentEntity = parentEntityRepository.findById(parentEntityId);
        if (parentEntity.isPresent()) {
            childEntity.setParent(parentEntity.get());
            childEntityRepository.save(childEntity);
            return childEntity;
        }
        throw new EntityNotFoundException("Parent entity not found!");
    }
}

考虑到这种方式，控制器几乎没有逻辑：它只是将请求转发到适当的服务，就像流量控制器一样。此外，使用这种方法，在未来的某一天，您必须添加一些“替代”控制器，例如 WebSocket 或旧式 WebService，您为此付出的努力将是最小的，并且您将最大限度地减少此控制器与任何未来之间的相似性控制器。 这种方法的黄金法则如下：DAO/Repository 总是返回 Entities，Service 总是返回 DTO。控制器只是外部世界的接口。