AutoWired JPA Repository 在某些控制器方法中为空

Question

I have a JPARepository like this

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

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

I then have a controller where I am initializing the Repository like this

@Autowired
RestaurantRepo restaurantRepo;

Then I have one method where I am using the Repository like this

@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);
    }

Whenever I hit this api, it works fine. Then I have another method like this

@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);
        }

    }

Here I get a NullPointerException in this line Optional<Restaurant> opt = restaurantRepo.findById(username);

The username is a valid username, and so when I print the restaurantRepo I get null .

I am confused as to why the variable is not null in one method while it is null in another method. Any help would be appreciated. Thanks

Answer 1

Im not sure. But try to change the access modifier in the second method to public .
Please refer this thread

Also use constructor injection instead of @Autowired annotation.