How to return HTTP response from HandlerMethodArgumentResolver - http

Question

I have some controller's method:
#RequestMapping("/")
#AuthorizedRNUser
public Object index(UserStateVO userStateVO) {
return userStateVO;
}
Also I have HandlerMethodArgumentResolver for UserStateVO parameter
public class UserStateArgumentHandlerResovler implements HandlerMethodArgumentResolver{
#Autowired
RNService service;
#Override
public boolean supportsParameter(MethodParameter methodParameter) {
return methodParameter.getMethod().isAnnotationPresent(AuthorizedRNUser.class) && methodParameter.getParameterType() == UserStateVO.class;
}
#Override
public Object resolveArgument(MethodParameter methodParameter, ModelAndViewContainer modelAndViewContainer, NativeWebRequest nativeWebRequest, WebDataBinderFactory webDataBinderFactory) throws Exception {
UserStateVO userState = service.getUserState();
if (isNull(userState))
// here i need to return 403 HTTP response
throw new RuntimeException("User is not allowed");
return userState;
}
}
And if the UserStateVO is null I need to return 403 HTTP response, but I do not know is it possible? How best to check UserStateVO and pass it into a controller or return HTTP response?

Answer 1

Use the same method as handling exceptions in MVC exception-handling-in-spring-mvc
Add your custom exception, e.g
public class BadRequestException extends RuntimeException {
private static final long serialVersionUID = 1L;
public BadRequestException(String message) {
super(message);
}
}
And either annotate it with #ResponseStatus(value = HttpStatus.FORBIDDEN, reason = "User is not allowed") or add #ControllerAdvice class with method like
#ExceptionHandler(value = { BadRequestException.class })
#ResponseStatus(value = HttpStatus.FORBIDDEN)
#ResponseBody
public Map<String, String> handleBadRequestException(BadRequestException e) {
Map<String, String> retMessages = new HashMap<>();
retMessages.put("message", e.getMessage());
return retMessages;
}
what remains is just to throw it
if (isNull(userState))
// here i need to return 403 HTTP response
throw new BadRequestException("User is not allowed");