apollo-common/src/main/java/com/ctrip/framework/apollo/common/controller/GlobalDefaultExceptionHandler.java/GlobalDefaultExceptionHandler/handleConstraintViolationException
class GlobalDefaultExceptionHandler:  @ExceptionHandler(ConstraintViolationException.class)
  public ResponseEntity<Map<String, Object>> handleConstraintViolationException(
      HttpServletRequest request, ConstraintViolationException ex
  ) {
    return handleError(request, BAD_REQUEST, new BadRequestException(ex.getMessage()));
  }