问题描述
我想在我的投资组合项目中添加春季阴影,并使其完全宁静。这意味着我需要重写AbstractResource类(这是我的@RestController的基类)给出的方法,以根据需要对其进行编辑,当我这样做时,我会收到org.springframework.dao.InvalidDataAccessApiUsageException:给定的id不能为null !
我的项目如下:
- 服务包
public interface AbstractService<ENTITY extends AbstractEntity> {
ENTITY update(ENTITY entity);
EntityModel<ENTITY> getById(Long id);
ENTITY save(ENTITY entity);
void delete(Long id);
Collection<ENTITY> getAll();
}
public abstract class AbstractServiceImpl<ENTITY extends AbstractEntity> implements AbstractService<ENTITY> {
protected abstract JpaRepository<ENTITY,Long> getRepository();
@Override
public Collection<ENTITY> getAll() {
return getRepository().findAll();
}
@Override
public EntityModel<ENTITY> getById(Long id) {
return EntityModel.of(getRepository().getone(id));
}
}
@Service
public class UserServiceImpl extends AbstractServiceImpl<User> implements UserService {
private final UserRepository userRepository;
@Override
protected JpaRepository<User,Long> getRepository() {
return userRepository;
}
}
- 资源包
public abstract class AbstractResource<ENTITY extends AbstractEntity>{
public abstract AbstractService<ENTITY> getService();
@GetMapping(value = "/{id}",produces = {"application/hal+json"})
public EntityModel<ENTITY> getById(@PathVariable("id") Long id) {
return getService().getById(id);
}
@GetMapping
public Collection<ENTITY> getAll() {
return getService().getAll();
}
}
当我这样离开时-一切正常-我得到预期的答复
@RestController
@RequestMapping("/api/users")
public class UserResource extends AbstractResource<User> {
@Autowired
private final UserService userService;
@Override
public AbstractService<User> getService() {
return userService;
}
}
@RestController
@RequestMapping("/api/users")
public class UserResource extends AbstractResource<User> {
@Autowired
private final UserService userService;
@Override
public AbstractService<User> getService() {
return userService;
}
@Override
public EntityModel<User> getById(Long id) {
return userService.getById(id);
or
return super.getById(id);
}
}
解决方法
在UserResource
覆盖AbstractResource.getById(Long)
之后,尽管注释@GetMapping(value = "/{id}",produces = {"application/hal+json"})
是继承的,但注释@PathVariable("id")
不是继承的。将注解@PathVariable("id")
放在UserResource.getById(Long)
中应该可以解决您的问题。
强烈建议将可运行的示例项目(包括请求URL和测试数据)放入Github中,以重现您遇到的错误。否则,很难找出原因并进行验证。