docs: public static String generateMchPayNativeRequestURL(String appid, String mch_id, String productid, String key) {
  		Map<String, String> map = new LinkedHashMap<String, String>();
  		map.put("appid", appid);
  		map.put("mch_id", mch_id);
  		map.put("time_stamp", System.currentTimeMillis() / 1000 + "");
  		map.put("nonce_str", UUID.randomUUID().toString().replace("-", ""));
  		map.put("product_id", productid);
  		String sign = SignatureUtil.generateSign(map, key);
  		map.put("sign", sign);
  		return "weixin://wxpay/bizpayurl?" + MapUtil.mapJoin(map, false, false);
  	}