Can i send a error-map along with a response object in response? What is the proper way? - spring

Question

I have a spring rest end point which accepts a user object and returns another userobject as response. My controller method looks like:
#PostMapping
public UserResponse createUser(#RequestBody UserDetailsRequestModel userDetails)
throws Exception {
UserRest userResponse= new UserRest();
ModelMapper modelMapper = new ModelMapper();
UserDto userDto = modelMapper.map(userDetails, UserDto.class);
userDto.setRoles(new HashSet<>(Arrays.asList(Roles.ROLE_USER.name())));
UserDto createdUser = userService.createUser(userDto);
returnValue = modelMapper.map(createdUser, UserResponse.class);
return userResponse;
}
My userResponse class looks like
public class UserRest {
private String userId;
private String firstName;
private String lastName;
private String email;
....getters and setters
And this flow is working fine. But now I need to add validation to createUser method (JSR 303) to check if incoming JSON fields are ok. For this I am trying to add below code in my controller
#PostMapping
public UserResponse createUser(#Valid #RequestBody UserDetailsRequestModel userDetails, BindingResult result){
if(result.hasErrors()){
Map<String, String> errorMap = new HashMap<>();
for(FieldError error: result.getFieldErrors()){
errorMap.put(error.getField(), error.getDefaultMessage());
}
**return new ResponseEntity<Map<String, String>>(errorMap, HttpStatus.BAD_REQUEST);**
}
UserRest userResponse= new UserRest();
ModelMapper modelMapper = new ModelMapper();
UserDto userDto = modelMapper.map(userDetails, UserDto.class);
userDto.setRoles(new HashSet<>(Arrays.asList(Roles.ROLE_USER.name())));
UserDto createdUser = userService.createUser(userDto);
returnValue = modelMapper.map(createdUser, UserResponse.class);
return **userResponse**;
The obvious problem in my code is that I can't convert from ResponseEntity<Map<String,String>> to UserResponse object.
Is there a proper way of doing this ? so that I can send errors(if any) or the UserResponse object if there are no errors within the same controller method?

Answer 1

Return a type of ResponseEntity<?>
#PostMapping
public ResponseEntity<?> createUser(#Valid #RequestBody UserDetailsRequestModel userDetails, BindingResult result){
if(result.hasErrors()){
...
return ResponseEntity.badRequest().body(errorMap);
}
...
return ResponseEntity.ok(userRequest);
}

Answer 2

You can return an HttpEntity<?> generic object from a controller method accepting both response type.
You have to wrap the UserResponse response around a ResponseEntity object