英文:
After overriding RestController method I get: org.springframework.dao.InvalidDataAccessApiUsageException: The given id must not be null
问题
我想将 spring-hateoas 添加到我的作品集项目中，并使其完全符合 RESTful。这意味着我需要覆盖 AbstractResource 类提供的方法（这是我 @RestController 的基类），以便根据我的需求进行编辑。当我这样做时，我会遇到 org.springframework.dao.InvalidDataAccessApiUsageException: 给定的 id 不得为空！
我的项目结构如下：
- service 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();@Overridepublic Collection<ENTITY> getAll() {return getRepository().findAll();}@Overridepublic EntityModel<ENTITY> getById(Long id) {return EntityModel.of(getRepository().getOne(id));}}@Servicepublic class UserServiceImpl extends AbstractServiceImpl<User> implements UserService {private final UserRepository userRepository;@Overrideprotected JpaRepository<User, Long> getRepository() {return userRepository;}}
- resource 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);}@GetMappingpublic Collection<ENTITY> getAll() {return getService().getAll();}}
当我保持这样 - 一切正常工作 - 我按预期获得响应：
@RestController@RequestMapping("/api/users")public class UserResource extends AbstractResource<User> {@Autowiredprivate final UserService userService;@Overridepublic AbstractService<User> getService() {return userService;}}
当我尝试覆盖此方法时，出现错误：
@RestController@RequestMapping("/api/users")public class UserResource extends AbstractResource<User> {@Autowiredprivate final UserService userService;@Overridepublic AbstractService<User> getService() {return userService;}@Overridepublic EntityModel<User> getById(Long id) {return userService.getById(id);或return super.getById(id);}}
英文:
I want to add spring-hateoas to my portfolio project and make it fully restful. That means that I need to override methods given by AbstractResource class(this is base class for my @RestController's) to edit it for my needs and when I do so I get org.springframework.dao.InvalidDataAccessApiUsageException: The given id must not be null!
My project look as follows:
- service package
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();@Overridepublic Collection<ENTITY> getAll() {return getRepository().findAll();}@Overridepublic EntityModel<ENTITY> getById(Long id) {return EntityModel.of(getRepository().getOne(id));}}@Servicepublic class UserServiceImpl extends AbstractServiceImpl<User> implements UserService {private final UserRepository userRepository;@Overrideprotected JpaRepository<User, Long> getRepository() {return userRepository;}}
- resource package
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);}@GetMappingpublic Collection<ENTITY> getAll() {return getService().getAll();}}
When I leave this like so - everything works normal - I get responses as expected
@RestController@RequestMapping("/api/users")public class UserResource extends AbstractResource<User> {@Autowiredprivate final UserService userService;@Overridepublic AbstractService<User> getService() {return userService;}}
Error ocurrs when I try to override this method
@RestController@RequestMapping("/api/users")public class UserResource extends AbstractResource<User> {@Autowiredprivate final UserService userService;@Overridepublic AbstractService<User> getService() {return userService;}@Overridepublic EntityModel<User> getById(Long id) {return userService.getById(id);orreturn super.getById(id);}}
答案1
得分: 0
在UserResource覆盖AbstractResource.getById(Long)之后，尽管@GetMapping(value = "/{id}", produces = {"application/hal+json"})注解是继承的，但@PathVariable("id")注解却没有被继承。将@PathVariable("id")注解放在UserResource.getById(Long)内部应该可以解决你的问题。
强烈建议在Github上放置一个可运行的示例项目（包括请求URL和测试数据），以重现你遇到的错误。否则，很难找出错误的原因并进行验证。
英文:
After UserResource overrides AbstractResource.getById(Long), though the annotation @GetMapping(value = "/{id}", produces = {"application/hal+json"}) is inherited, the annotation @PathVariable("id") is not. Put the annotation @PathVariable("id") within UserResource.getById(Long) should solve your problem.
It's highly recommended to put a runnable sample project (including request URL and test data) in Github to reproduce the error you encountered. Otherwise, it's difficult to find out the cause and verify.
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