code: public static String getCodeUrl(String appid, String mch_id, String product_id, String partnerKey,
  			boolean isToShortUrl) {
  		String url = "weixin://wxpay/bizpayurl?sign=XXXXX&appid=XXXXX&mch_id=XXXXX&product_id=XXXXX&time_stamp=XXXXX&nonce_str=XXXXX";
  		String timeStamp = Long.toString(System.currentTimeMillis() / 1000);
  		String nonceStr = Long.toString(System.currentTimeMillis());
  		Map<String, String> packageParams = new HashMap<String, String>();
  		packageParams.put("appid", appid);
  		packageParams.put("mch_id", mch_id);
  		packageParams.put("product_id", product_id);
  		packageParams.put("time_stamp", timeStamp);
  		packageParams.put("nonce_str", nonceStr);
  		String packageSign = PaymentKit.createSign(packageParams, partnerKey);
  		String qrCodeUrl = PaymentKit.replace(url, "XXXXX", packageSign, appid, mch_id, product_id, timeStamp,
  				nonceStr);
  		if (isToShortUrl) {
  			String shortResult = WxPayApi
  					.toShortUrl(PaymentKit.buildShortUrlParasMap(appid, null, mch_id, null, qrCodeUrl, partnerKey));
  			Map<String, String> shortMap = PaymentKit.xmlToMap(shortResult);
  			String return_code = shortMap.get("return_code");
  			if (PaymentKit.codeIsOK(return_code)) {
  				String result_code = shortMap.get("result_code");
  				if (PaymentKit.codeIsOK(result_code)) {
  					qrCodeUrl = shortMap.get("short_url");
  				}
  			}
  		}
  
  		return qrCodeUrl;
  	}
docs: 商户模式下 扫码模式一之生成二维码
  
  @param appid
  @param mch_id
  @param product_id
  @param partnerKey
  @param isToShortUrl
  是否转化为短连接
  @return {String}