微信支付V3版本地签名统一下单android端详解

满满的都是坑，因为服务器偷懒让客服端写统一下单，服务器只给了通知的url。微信的支付demo并没有统一下单的代码。

读此文前先阅读 https://pay.weixin.qq.com/wiki/doc/api/app/app.php?chapter=9_1

一步步的来  先根据统一下单的参数介绍工具：

1. 获取到当前的ip：

<span style="font-size:14px;">public String getLocalIpAddress() {try {for (Enumeration<NetworkInterface> en = NetworkInterface.getNetworkInterfaces(); en.hasMoreElements(); ) {NetworkInterface intf = en.nextElement();for (Enumeration<InetAddress> enumIpAddr = intf.getInetAddresses(); enumIpAddr.hasMoreElements(); ) {InetAddress inetAddress = enumIpAddr.nextElement();if (!inetAddress.isLoopbackAddress()) {return inetAddress.getHostAddress().toString();}}}} catch (SocketException ex) {}return null;}private String getWifiIp() {//获取wifi服务WifiManager wifiManager = (WifiManager) getSystemService(Context.WIFI_SERVICE);//判断wifi是否开启if (!wifiManager.isWifiEnabled()) {wifiManager.setWifiEnabled(true);}WifiInfo wifiInfo = wifiManager.getConnectionInfo();int ipAddress = wifiInfo.getIpAddress();String ip = intToIp(ipAddress);return ip;}private String intToIp(int i) {return (i & 0xFF) + "." +((i >> 8) & 0xFF) + "." +((i >> 16) & 0xFF) + "." +(i >> 24 & 0xFF);}</span>

2.随机订单号生成 test 你们可根据自己生成随机数：

<span style="font-size:14px;">private String genOutTradNo() {Random random = new Random();return MD5.getMessageDigest(String.valueOf(random.nextInt(10000)).getBytes());}</span>

3.签名工具：

<span style="font-size:14px;">private String genAppSign(List<NameValuePair> params) {StringBuilder sb = new StringBuilder();for (int i = 0; i < params.size(); i++) {sb.append(params.get(i).getName());sb.append('=');sb.append(params.get(i).getValue());sb.append('&');}sb.append("key=");sb.append(Constants.API_KEY);this.sb.append("sign str\n"+sb.toString()+"\n\n");String appSign = MD5.getMessageDigest(sb.toString().getBytes());Log.e("orion",appSign);return appSign;}</span>

差不多了  现在我们需要生成传递的参数   参数要求是xml 格式的：

<span style="font-size:14px;">private String genProductArgs() {StringBuffer xml = new StringBuffer();String ip = getWifiIp();if (ip == "" && ip == "") {ip = getLocalIpAddress();}try {StringnonceStr = genNonceStr();xml.append("</xml>");List<NameValuePair> packageParams = new LinkedList<NameValuePair>();packageParams.add(new BasicNameValuePair("appid", Constants.APP_ID));packageParams.add(new BasicNameValuePair("body", "APP pay test"));packageParams.add(new BasicNameValuePair("mch_id", Constants.MCH_ID));packageParams.add(new BasicNameValuePair("nonce_str", nonceStr));packageParams.add(new BasicNameValuePair("notify_url",ConfigUtil.NOTIFY_URL));packageParams.add(new BasicNameValuePair("out_trade_no",genOutTradNo()));packageParams.add(new BasicNameValuePair("spbill_create_ip",ip));packageParams.add(new BasicNameValuePair("total_fee", "1"));packageParams.add(new BasicNameValuePair("trade_type", "APP"));String sign = genPackageSign(packageParams);packageParams.add(new BasicNameValuePair("sign", sign));String xmlstring =toXml(packageParams);return xmlstring;} catch (Exception e) {Log.e("TAG", "fail, ex = " + e.getMessage());return null;}}</span>

其中  toxml：

<span style="font-size:14px;">private String toXml(List<NameValuePair> params) {StringBuilder sb = new StringBuilder();sb.append("<xml>");for (int i = 0; i < params.size(); i++) {sb.append("<"+params.get(i).getName()+">");sb.append(params.get(i).getValue());sb.append("</"+params.get(i).getName()+">");}sb.append("</xml>");Log.e("orion",sb.toString());return sb.toString();}</span>

得到传递的参数，根据文档指示，我们需要用post去吊连接URL地址：https://api.mch.weixin.qq.com/pay/unifiedorder：

<span style="font-size:14px;">private class GetPrepayIdTask extends AsyncTask<Void, Void, Map<String,String>> {private ProgressDialog dialog;@Overrideprotected void onPreExecute() {dialog = ProgressDialog.show(PayActivity.this, getString(R.string.app_tip), getString(R.string.getting_prepayid));}@Overrideprotected void onPostExecute(Map<String,String> result) {if (dialog != null) {dialog.dismiss();}sb.append("prepay_id\n"+result.get("prepay_id")+"\n\n");resultunifiedorder=result;}@Overrideprotected void onCancelled() {super.onCancelled();}@Overrideprotected Map<String,String>  doInBackground(Void... params) {String url = String.format("https://api.mch.weixin.qq.com/pay/unifiedorder");String entity = genProductArgs();Log.e("orion",entity);byte[] buf = Util.httpPost(url, entity);String content = new String(buf);Log.e("orion", content);Map<String,String> xml=decodeXml(content);return xml;}}</span>

其中decodexml就是：

<span style="font-size:14px;">public Map<String,String> decodeXml(String content) {try {Map<String, String> xml = new HashMap<String, String>();XmlPullParser parser = Xml.newPullParser();parser.setInput(new StringReader(content));int event = parser.getEventType();while (event != XmlPullParser.END_DOCUMENT) {String nodeName=parser.getName();switch (event) {case XmlPullParser.START_DOCUMENT:break;case XmlPullParser.START_TAG:if("xml".equals(nodeName)==false){//实例化student对象xml.put(nodeName,parser.nextText());}break;case XmlPullParser.END_TAG:break;}event = parser.next();}return xml;} catch (Exception e) {Log.e("orion",e.toString());}return null;}</span>

下单完成，第二部就是给微信支付传递调起微信支付的参数（具体参数看文档说明）：

<span style="font-size:14px;">private void genPayReq() {req.appId = Constants.APP_ID;req.partnerId = Constants.MCH_ID;req.prepayId = resultunifiedorder.get("prepay_id");req.packageValue = "prepay_id="+resultunifiedorder.get("prepay_id");req.nonceStr = genNonceStr();req.timeStamp = String.valueOf(genTimeStamp());List<NameValuePair> signParams = new LinkedList<NameValuePair>();signParams.add(new BasicNameValuePair("appid", req.appId));signParams.add(new BasicNameValuePair("noncestr", req.nonceStr));signParams.add(new BasicNameValuePair("package", req.packageValue));signParams.add(new BasicNameValuePair("partnerid", req.partnerId));signParams.add(new BasicNameValuePair("prepayid", req.prepayId));signParams.add(new BasicNameValuePair("timestamp", req.timeStamp));req.sign = genAppSign(signParams);sb.append("sign\n"+req.sign+"\n\n");Log.e("orion", signParams.toString());}</span>

第三部，调微信支付：

<span style="font-size:14px;">private void sendPayReq() {msgApi.registerApp(Constants.APP_ID);msgApi.sendReq(req);}</span>

其中：

<span style="font-size:14px;">Constants.APP_ID</span>

是appid 在开发者平台获取

<span style="font-size:14px;">req.partnerId = Constants.MCH_ID;</span>

商户id

<span style="font-size:14px;">ConfigUtil.NOTIFY_URL</span>

支付后的回调通知地址。

签名两次，然后用的api——key是商户平台api安全里面自定义的。

对了 还有个获取时间工具

<span style="font-size:14px;">private long genTimeStamp() {return System.currentTimeMillis() / 1000;}</span>

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