code: public Controller keepPara(Class type, String name) {
  		String[] values = request.getParameterValues(name);
  		if (values != null) {
  			if (values.length == 1)
  				try {request.setAttribute(name, TypeConverter.me().convert(type, values[0]));} catch (ParseException e) {com.jfinal.kit.LogKit.logNothing(e);}
  			else
  				request.setAttribute(name, values);
  		}
  		return this;
  	}
docs: Convert para to special type and keep it