code: protected void validateDouble(String field, double min, double max, String errorKey, String errorMessage) {
  		String value = controller.getPara(field);
  		if (StrKit.isBlank(value)) {
  			addError(errorKey, errorMessage);
  			return ;
  		}
  		try {
  			double temp = Double.parseDouble(value.trim());
  			if (temp < min || temp > max) {
  				addError(errorKey, errorMessage);
  			}
  		}
  		catch (Exception e) {
  			addError(errorKey, errorMessage);
  		}
  	}
docs: Validate double.