#Valid | response very verbose, how to customize? - spring-boot

Question

I have a Spring Boot microservice and I want to valide the incoming requestBody of an endpoint.
By using #Valid with #NotBlank I have noticed that the answer is very verbose and my customized error message is deep into the object; here is an example:
{
"timestamp": "2020-12-17T09:28:26.529+0000",
"status": 400,
"error": "Bad Request",
"errors": [
{
"codes": [
"NotBlank.createUserRequest.username",
"NotBlank.username",
"NotBlank.java.lang.String",
"NotBlank"
],
"arguments": [
{
"codes": [
"createUserRequest.username",
"username"
],
"arguments": null,
"defaultMessage": "username",
"code": "username"
}
],
"defaultMessage": "USERNAME IS REQUIRED",
"objectName": "createUserRequest",
"field": "username",
"rejectedValue": "",
"bindingFailure": false,
"code": "NotBlank"
}
],
"message": "Validation failed for object='createUserRequest'. Error count: 1",
"path": "/api/user/create"
}
How can I customize this object returned? I would like the response to simply be something like this:
{
"timestamp": "2020-12-17T09:28:26.529+0000",
"status": 400,
"error": "Bad Request",
"message": "USERNAME IS REQUIRED"
}
Here is my code:
Request
#Data
public class CreateUserRequest {
#NotBlank(message = "username is required")
private String username;
#Size(min = 3, max = 64)
#NotBlank(message = "password is required")
private String password;
#NotBlank(message = "confirmPassword is required")
#Size(min = 3, max = 64)
private String confirmPassword;
}
Controller
#PostMapping("/create")
public ResponseEntity<User> createUser(#Valid #RequestBody CreateUserRequest request) {
User user = appService.createUserAndCart(request);
return ResponseEntity.ok(user);
}
Thank you for your experience

Answer 1

You can use #ControllerAdvice/#RestControllerAdvice
it allows you to handle exceptions across the whole application. You can think of it as an interceptor of exceptions thrown by methods annotated with #RequestMapping and similar.
And add a method like this,
#ExceptionHandler(Exception.class)
public ResponseEntity<Object> handleException(Exception ex)
//your custom body
return new ResponseEntity<>(body, HttpStatus.XXXXX);
}
You can specify a specific Exception type (I think it's InvalidArgumentException in your case)

Answer 2

Define a return class
import org.springframework.http.HttpStatus;
import java.util.HashMap;
/**
* #description:
* #author: 582895699#qq.com
* #time: 2020/12/20 下午 01:50
*/
public class Resp extends HashMap {
private static final long serialVersionUID = 1L;
public static final String TIMESTAMP = "timestamp";
public static final String STATUS = "status";
public static final String ERROR = "error";
public static final String MESSAGE = "message";
public static Resp fail(String message) {
Resp resp = new Resp();
resp.put(TIMESTAMP, System.currentTimeMillis());
resp.put(STATUS, HttpStatus.BAD_REQUEST.value());
resp.put(ERROR, HttpStatus.BAD_REQUEST.getReasonPhrase());
resp.put(MESSAGE, message);
return resp;
}
#Override
public Object put(Object key, Object value) {
return super.put(key, value);
}
}
Define global exception handling class and obtain exception information
import org.springframework.validation.BindingResult;
import org.springframework.validation.ObjectError;
import org.springframework.web.bind.MethodArgumentNotValidException;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestControllerAdvice;
/**
* #description:
* #author: 582895699#qq.com
* #time: 2020/12/20 下午 01:55
*/
#RestControllerAdvice
public class GlobalExceptionHandler {
#ExceptionHandler(value = MethodArgumentNotValidException.class)
public Resp methodArgumentNotValidExceptionHandler(MethodArgumentNotValidException e) {
BindingResult bindingResult = e.getBindingResult();
ObjectError objectError = bindingResult.getAllErrors().get(0);
String message = objectError.getDefaultMessage();
return Resp.fail(message);
}
}