SpringBoot Validation

.java

@Entity
public class Customer {

	@Id
	@GeneratedValue(strategy=GenerationType.SEQUENCE)
	private @Getter Integer id;
	@NotNull
	@Size(min=6, max=50)
  @Valid
	private @Getter String password;
}


@RepositoryRestResource(path="/customer",
collectionResourceRel="/customer")
public interface CustomerRepository extends PagingAndSortingRepository<Customer, Integer> {

}


@Order(Ordered.HIGHEST_PRECEDENCE)
@ControllerAdvice(basePackageClasses = { ConstraintViolationException.class, RepositoryRestExceptionHandler.class,
		TransactionSystemException.class })
public class CustomRestExceptionHandler extends ResponseEntityExceptionHandler {

	@Override
	protected ResponseEntity<Object> handleMethodArgumentNotValid(MethodArgumentNotValidException ex,
			HttpHeaders headers, HttpStatus status, WebRequest request) {
		
		List<String> errors = new ArrayList<String>();
		
		for (FieldError error : ex.getBindingResult().getFieldErrors()) {
			errors.add(error.getField() + ": " + error.getDefaultMessage());
		}
		
		for (ObjectError error : ex.getBindingResult().getGlobalErrors()) {
			errors.add(error.getObjectName() + ": " + error.getDefaultMessage());
		}

		ApiError apiError = new ApiError(HttpStatus.BAD_REQUEST, ex.getLocalizedMessage(), errors);
		return handleExceptionInternal(ex, apiError, headers, apiError.getStatus(), request);
	}

	@Override
	protected ResponseEntity<Object> handleMissingServletRequestParameter(MissingServletRequestParameterException ex,
			HttpHeaders headers, HttpStatus status, WebRequest request) {
		String error = ex.getParameterName() + " parameter is missing";

		ApiError apiError = new ApiError(HttpStatus.BAD_REQUEST, ex.getLocalizedMessage(), error);
		return new ResponseEntity<Object>(apiError, new HttpHeaders(), apiError.getStatus());
	}

	@ExceptionHandler({ ConstraintViolationException.class })
	public ResponseEntity<Object> handleConstraintViolation(ConstraintViolationException ex, WebRequest request) {
		
		List<String> errors = new ArrayList<String>();
		
		for (ConstraintViolation<?> violation : ex.getConstraintViolations()) {
			errors.add(violation.getRootBeanClass().getName() + " " + violation.getPropertyPath() + ": "
					+ violation.getMessage());
		}

		ApiError apiError = new ApiError(HttpStatus.BAD_REQUEST, ex.getLocalizedMessage(), errors);
		return new ResponseEntity<Object>(apiError, new HttpHeaders(), apiError.getStatus());
	}

	@ExceptionHandler({ MethodArgumentTypeMismatchException.class })
	public ResponseEntity<Object> handleMethodArgumentTypeMismatch(MethodArgumentTypeMismatchException ex,
			WebRequest request) {
		
		String error = ex.getName() + " should be of type " + ex.getRequiredType().getName();

		ApiError apiError = new ApiError(HttpStatus.BAD_REQUEST, ex.getLocalizedMessage(), error);
		return new ResponseEntity<Object>(apiError, new HttpHeaders(), apiError.getStatus());
	}
}