Java AutoWired JPA存储库在控制器的某些方法中为空

我有一个像这样的假设

@Repository
public interface RestaurantRepo extends JpaRepository<Restaurant, String> {
    Optional<Restaurant> findByName(String name);

    Optional<List<Restaurant>> findAllByMerchantId(String merchantId);
}

@Autowired
RestaurantRepo restaurantRepo;

@PreAuthorize("hasRole('ROLE_SUPER_ADMIN')")
    @GetMapping("/disable")
    public ResponseEntity<CustomResponse> disableUser(String username, boolean disable) {

        Restaurant restaurant = restaurantRepo.findById(username).get();
        restaurant.setDisabled(disable);

        CustomResponse er = new CustomResponse();
        er.setStatus("Successful");
        if (disable) {
            er.setMessage("Restaurant is disabled");
        } else {
            er.setMessage("Restaurant is enabled");
        }
        restaurantRepo.save(restaurant);
        return new ResponseEntity<>(er, new HttpHeaders(), HttpStatus.OK);
    }

@PreAuthorize("hasAnyRole('ROLE_SUPER_ADMIN','ROLE_RESTAURANT')")
    @GetMapping("/get")
    private ResponseEntity<Restaurant> getRestaurant(Principal principal) {
        String username = principal.getName();
        System.out.println("username "+username); //prints the valid username
        System.out.println("RestRepo "+restaurantRepo); //prints null
        Restaurant restaurant;
        Optional<Restaurant> opt = restaurantRepo.findById(username); //prints Exception here
        if (opt.isPresent()) {
            restaurant = opt.get();
            return new ResponseEntity<>(restaurant, HttpStatus.OK);
        } else {
            restaurant = new Restaurant();
            return new ResponseEntity<>(restaurant, HttpStatus.NOT_FOUND);
        }

    }

然后我有一种方法，我使用的存储库如下

@Repository
public interface RestaurantRepo extends JpaRepository<Restaurant, String> {
    Optional<Restaurant> findByName(String name);

    Optional<List<Restaurant>> findAllByMerchantId(String merchantId);
}

@Autowired
RestaurantRepo restaurantRepo;

@PreAuthorize("hasRole('ROLE_SUPER_ADMIN')")
    @GetMapping("/disable")
    public ResponseEntity<CustomResponse> disableUser(String username, boolean disable) {

        Restaurant restaurant = restaurantRepo.findById(username).get();
        restaurant.setDisabled(disable);

        CustomResponse er = new CustomResponse();
        er.setStatus("Successful");
        if (disable) {
            er.setMessage("Restaurant is disabled");
        } else {
            er.setMessage("Restaurant is enabled");
        }
        restaurantRepo.save(restaurant);
        return new ResponseEntity<>(er, new HttpHeaders(), HttpStatus.OK);
    }

@PreAuthorize("hasAnyRole('ROLE_SUPER_ADMIN','ROLE_RESTAURANT')")
    @GetMapping("/get")
    private ResponseEntity<Restaurant> getRestaurant(Principal principal) {
        String username = principal.getName();
        System.out.println("username "+username); //prints the valid username
        System.out.println("RestRepo "+restaurantRepo); //prints null
        Restaurant restaurant;
        Optional<Restaurant> opt = restaurantRepo.findById(username); //prints Exception here
        if (opt.isPresent()) {
            restaurant = opt.get();
            return new ResponseEntity<>(restaurant, HttpStatus.OK);
        } else {
            restaurant = new Restaurant();
            return new ResponseEntity<>(restaurant, HttpStatus.NOT_FOUND);
        }

    }

@预授权（“hasRole（'ROLE\u SUPER\u ADMIN'））
@GetMapping（“/disable”）
公共响应属性禁用用户（字符串用户名，布尔禁用）{
Restaurant Restaurant=restaurantRepo.findById（用户名）.get（）；
餐厅。设置禁用（禁用）；
CustomResponse er=新CustomResponse（）；
er.setStatus（“成功”）；
如果（禁用）{
er.setMessage（“餐厅被禁用”）；
}否则{
er.setMessage（“餐厅已启用”）；
}
拯救餐厅（餐厅）；
返回新的ResponseEntity（呃，newhttpheaders（），HttpStatus.OK）；
}

每当我使用这个api时，它都可以正常工作。 然后我有另一种方法像这样

@Repository
public interface RestaurantRepo extends JpaRepository<Restaurant, String> {
    Optional<Restaurant> findByName(String name);

    Optional<List<Restaurant>> findAllByMerchantId(String merchantId);
}

@Autowired
RestaurantRepo restaurantRepo;

@PreAuthorize("hasRole('ROLE_SUPER_ADMIN')")
    @GetMapping("/disable")
    public ResponseEntity<CustomResponse> disableUser(String username, boolean disable) {

        Restaurant restaurant = restaurantRepo.findById(username).get();
        restaurant.setDisabled(disable);

        CustomResponse er = new CustomResponse();
        er.setStatus("Successful");
        if (disable) {
            er.setMessage("Restaurant is disabled");
        } else {
            er.setMessage("Restaurant is enabled");
        }
        restaurantRepo.save(restaurant);
        return new ResponseEntity<>(er, new HttpHeaders(), HttpStatus.OK);
    }

@PreAuthorize("hasAnyRole('ROLE_SUPER_ADMIN','ROLE_RESTAURANT')")
    @GetMapping("/get")
    private ResponseEntity<Restaurant> getRestaurant(Principal principal) {
        String username = principal.getName();
        System.out.println("username "+username); //prints the valid username
        System.out.println("RestRepo "+restaurantRepo); //prints null
        Restaurant restaurant;
        Optional<Restaurant> opt = restaurantRepo.findById(username); //prints Exception here
        if (opt.isPresent()) {
            restaurant = opt.get();
            return new ResponseEntity<>(restaurant, HttpStatus.OK);
        } else {
            restaurant = new Restaurant();
            return new ResponseEntity<>(restaurant, HttpStatus.NOT_FOUND);
        }

    }

@预授权（“hasAnyRole（'ROLE\u SUPER\u ADMIN'，'ROLE\u RESTAURANT'））
@GetMapping（“/get”）
私人餐厅（主要负责人）{
字符串username=principal.getName（）；
System.out.println（“用户名”+用户名）；//打印有效的用户名
System.out.println（“RestRepo”+restaurantRepo）；//打印空值
食肆;；
可选opt=restaurantRepo.findById（用户名）；//此处打印异常
if（opt.isPresent（））{
restaurant=opt.get（）；
返回新的ResponseEntity（餐厅，HttpStatus.OK）；
}否则{
餐厅=新餐厅（）；
返回新的ResponseEntity（餐厅、HttpStatus.未找到）；
}
}

在这里，我在这一行中得到一个NullPointerException

Optional=restaurantRepo.findById（用户名）

用户名是有效的用户名，因此当我打印
restaurantRepo
时，我得到
null

我不明白为什么变量在一个方法中不为null，而在另一个方法中为null。任何帮助都将不胜感激。谢谢，我不确定。但请尝试将第二种方法中的访问修饰符更改为public

请参考这个

也使用构造函数注入而不是@Autowired annotation。
方法disableUser和getRestaurant在同一控制器中吗？@Niyas是的，它们在同一控制器中