How do I customize default error message from spring @Valid validation?

Question

DTO:

public class User {

    @NotNull
    private String name;

    @NotNull
    private String password;

    //..
}

Controller:

Answer 1

One way to do it is adding message in @NotNull annotation on entity properties. And adding @Valid annotation in controller request body.

DTO:

public class User {
   
    @NotNull(message = "User name cannot be empty")
    private String name;

    @NotNull(message = "Password cannot be empty")
    private String password;

    //..
}

Controller:

@RequestMapping(value = "/user", method = RequestMethod.POST)
public ResponseEntity<String> saveUser(@Valid @RequestBody User user) {
    //..
    return new ResponseEntity<>(HttpStatus.OK);
}
// Add one 
@ExceptionHandler(MethodArgumentNotValidException.class)
public ResponseEntity<List<YourErrorResponse>> handleException(MethodArgumentNotValidException ex) {
// Loop through FieldErrors in ex.getBindingResult();
// return *YourErrorReponse* filled using *fieldErrors*
}

Answer 2

For customized the error message in JSON format then do the below steps.

- Create one @Component called CommonErrorHandler

@Component
public class CommonErrorHandler {
public  Map<String,Object> getFieldErrorResponse(BindingResult result){

        Map<String, Object> fielderror = new HashMap<>();
        List<FieldError>errors= result.getFieldErrors();
        for (FieldError error : errors) {
            fielderror.put(error.getField(), error.getDefaultMessage());
        }return fielderror;
    }

     public ResponseEntity<Object> fieldErrorResponse(String message,Object fieldError){
        Map<String, Object> map = new HashMap<>();
        map.put("isSuccess", false);
        map.put("data", null);
        map.put("status", HttpStatus.BAD_REQUEST);
        map.put("message", message);
        map.put("timeStamp", DateUtils.getSysDate());
        map.put("filedError", fieldError);
        return new ResponseEntity<Object>(map,HttpStatus.BAD_REQUEST);
    }
}

-- Add InvalidException class

public class InvalidDataException extends RuntimeException {

/**
 * @author Ashok Parmar
 */
    private static final long serialVersionUID = -4164793146536667139L;

    private BindingResult result;

    public InvalidDataException(BindingResult result) {
        super();
        this.setResult(result);
    }

    public BindingResult getResult() {
        return result;
    }

    public void setResult(BindingResult result) {
        this.result = result;
    }

}

- Introduce @ControllerAdvice class

@ControllerAdvice
public class GlobalExceptionHandler extends ResponseEntityExceptionHandler {

@ExceptionHandler(InvalidDataException.class)
    public ResponseEntity<?> invalidDataException(InvalidDataException ex, WebRequest request) {

        List<FieldError> errors = ex.getResult().getFieldErrors();
        for (FieldError error : errors) {
            logger.error("Filed Name ::: " + error.getField() + "Error Message :::" + error.getDefaultMessage());
        }
        return commonErrorHandler.fieldErrorResponse("Error", commonErrorHandler.getFieldErrorResponse(ex.getResult()));
    }
    }

-- Use in controller with @Valid and throw exception

public AnyBeans update(**@Valid** @RequestBody AnyBeans anyBeans ,
            BindingResult result) {
        AnyBeans resultStr = null;
        if (result.hasErrors()) {
            **throw new InvalidDataException(result);**
        } else {
                resultStr = anyBeansService.(anyBeans );
                return resultStr;
        }
    }

-- Output will be in JSON format

{
  "timeStamp": 1590500231932,
  "data": null,
  "message": "Error",
  "isSuccess": false,
  "status": "BAD_REQUEST",
  "filedError": {
    "name": "Name is mandatory"
  }
}

Hope this will be work. :-D

Answer 3

You can do something like this

@ExceptionHandler(value = MethodArgumentNotValidException.class)
      protected ResponseEntity<Error> handleGlobalExceptions(MethodArgumentNotValidException ex,
          WebRequest request) {
        log.catching(ex);
        return new ResponseEntity<>(createErrorResp(HttpStatus.BAD_REQUEST,
            ex.getBindingResult().getFieldErrors().stream().map(err -> err.getDefaultMessage())
                .collect(java.util.stream.Collectors.joining(", "))),
            HttpStatus.BAD_REQUEST);
      }

Answer 4

{
  "message": "string",
  "errors": [
    {
      "field": "string",
      "message": "string",
      "error_code": "string"
    }
  ],
  "resource": "string",
  "description": "string"
}

Answer 5

Add some information too. If you use just @Valid, you need to catch BindException. If you use @Valid @RequestBody catch MethodArgumentNotValidException

Some sources:
HandlerMethodArgumentResolverComposite.getArgumentResolver(MethodParameter parameter):129 - search which HandlerMethodArgumentResolver support such parameter RequestResponseBodyMethodProcessor.supportsParameter(MethodParameter parameter) - return true if parameter has annotation @RequestBody

RequestResponseBodyMethodProcessor:139 - throw MethodArgumentNotValidException ModelAttributeMethodProcessor:164 - throw BindException

Answer 6

@ControllerAdvice(annotations = RestController.class)
public class GlobalExceptionHandler implements ApplicationContextAware {

    @ExceptionHandler(MethodArgumentNotValidException.class)
    @ResponseStatus(HttpStatus.OK)
    @ResponseBody
    public ApplicationError validationException(MethodArgumentNotValidException e) {

        e.printStackTrace();
        return new ApplicationError(SysMessageEnum.MSG_005, e.getBindingResult().getAllErrors().get(0).getDefaultMessage());

    }

}