java - Spring MVC - Rest API 是将实体放在一起的最佳位置

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 Controller 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 Controller 中，将dto映射到实体，然后将实体和父实体id发送给服务，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 Controller 几乎没有逻辑:它只是将请求转发到适当的服务，就像流量 Controller 一样。此外，使用这种方法，在未来的某一天你必须添加一些“替代” Controller ，如 WebSocket 或旧式 WebService，你这样做的工作量将是最小的，并且你将最大限度地减少此 Controller 与任何 future Controller 之间的相似性 Controller 。这种方法的黄金法则如下:DAOs/Repository 总是返回 Entities，Service 总是返回 DTOs。 Controller 只是外部世界的接口(interface)。