我们能否直接从服务层抛出ResponseStatusException而不会在控制器级别抛出自定义异常和处理？

Posted 2021-05-03

Spring 5引入了ResponseStatusException，这是直接从服务层抛出此异常的一种好习惯。

案例1：

@Service
public class UserService {
    public User findUserByName(String username) {
       User user = userRepository.findByUsernName(username);
       if(null == user) {
          throw new ResponseStatusException(HttpStatus.NOT_FOUND, "user not found");
       }
    }
}

案例2：还是我们需要使用自定义异常并在控制器级别处理它？在这种情况下，我们正在捕获CustomException并引发ResponseStatusException，为什么我们必须再次捕获该自定义异常，而不是使用Case 1

@Service
public class UserService {
    public User findUserByName(String username) {
       User user = userRepository.findByUsernName(username);
       if(null == user) {
          throw new UserNotFoundException("user not found");
       }
    }
}

@RestController
public class UserController {

    @GetMapping(path="/get-user")
    public ResponseEntity<User> getUser(String username) {
      try {
         userService.findUserByName(username);
      } catch (UserNotFoundException ex) {
         throw new ResponseStatusException(HttpStatus.NOT_FOUND, "user not found");
      }
    }
}

答案

正如评论中提到的，您可以在错误中创建映射。然后，您无需在控制器中使用try块。

import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.ResponseStatus;

@ResponseStatus(value = HttpStatus.NOT_FOUND, reason = "user not found")
public class UserNotFoundException extends RuntimeException {

    public UserNotFoundException(String message) {

        super(message);
    }
}