微信支付

public WeChatPayResponseData placeOrder(final WeChatPayRequestData request) {
    OneLevelOnlyXML xml = new OneLevelOnlyXML();
    xml.createRootElement("xml");
    for (StringPair param : sign(request.getSortedParameters())) {
      xml.createChild(param.getFirst(), param.getSecond());
    }
    String str = xml.toXMLString();
    LOG.info("Order request: {}", str);
    String ret = http.post("api.mch.weixin.qq.com", 443, "https", "/pay/unifiedorder", str);
    LOG.info("Order response: {}", ret);
    try {
      WeChatPayResponseData response = WeChatPayResponseData.parse(ret);
      String sign = signMD5(response.getAllData().getSorted("sign"));
      if (!sign.equalsIgnoreCase(response.getString("sign"))) {
        LOG.warn("Failed to verify sign");
        return null;
      }
      if (!"SUCCESS".equalsIgnoreCase(response.getString("return_code"))
          || !"SUCCESS".equalsIgnoreCase(response.getString("result_code"))) {
        LOG.warn("Error returned {}", response.getString("return_msg"));
        return null;
      }
      // return response.getString("prepay_id");
      response.setXml(ret);
      return response;
    } catch (UnsupportedEncodingException e) {
      LOG.warn("Cannot parse result", e);
      return null;
    } catch (ParserConfigurationException e) {
      LOG.warn("Cannot parse result", e);
      return null;
    } catch (SAXException e) {
      LOG.warn("Cannot parse result", e);
      return null;
    } catch (IOException e) {
      LOG.warn("Cannot parse result", e);
      return null;
    }
  }