这几天给app对接了微信支付，官方的demo真是。。。第一次果然不免爬几个坑，记录一下，避免遗忘。
错误说明
- 在保证提供的参数都正确的情况下，往往测试微信支付失败的原因是签名错误，这个时候应该仔细核对流程。就我自己而言碰到的问题就是搞错了最后发送订单的时候的签名sign参数。这个签名不是第一次组拼的签名，也不是生成预支付交易单，获取prepayId时返回的签名，而是获取到prepayId后用prepayId和其他参数第二次组拼成的sign。
流程说明
- 详细的业务流程为微信官方文档里有，我这边以所有参数由客户端提供的方式简单说明一下请求流程。
获取必须参数，第一次签名。
需要说明的是签名中的key参数是由我方自行在微信商户平台设置的。具体位置：微信商户平台(pay.weixin.qq.com)-->账户设置-->API安全-->密钥设置生成预支付交易单，获取prepayId。
调用微信的接口“https://api.mch.weixin.qq.com/pay/unifiedorder”获取prepayId。另外返回信息中的sign并不是最后调起支付中的sign参数。第二次签名。
用"appid"，"noncestr"，"package"，"partnerid"，"prepayid"，"timestamp"生成第二次签名。签名方式与第一次相同，参数不同(注意参数顺序)。这样就拿到了调起微信支付所需的所有参数。调起微信支付。
代码说明
public class WXPayUtils {
private Context mContext;
private PayReq req;
private IWXAPI iwxapi; //微信支付api
private Map<String, String> resultunifiedorder;
public WXPayUtils() {
}
public WXPayUtils(Context context) {
this.mContext = context;
req = new PayReq();
iwxapi = WXAPIFactory.createWXAPI(context, null); //初始化微信api
}
private Handler handler = new Handler() {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case 0: //获取参数及调起支付
getPayParameter();
sendPayReq();
break;
default:
break;
}
}
};
/**
* 第一次签名及生成prepayId
**/
public void toWXPayAndSign(int money) {
PrePayIdAsyncTask prePayIdAsyncTask = new PrePayIdAsyncTask();
prePayIdAsyncTask.execute(money);
}
private class PrePayIdAsyncTask extends AsyncTask<Integer, Void, Map<String, String>> {
@Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
}
@Override
protected Map<String, String> doInBackground(Integer... params) {
// TODO Auto-generated method stub
String urlString = "https://api.mch.weixin.qq.com/pay/unifiedorder";
int money = params[0];
String entity = getProductArgs(money);
Log.e("Simon", ">>>>" + entity);
byte[] buf = Util.httpPost(urlString, entity);
String content = new String(buf);
Log.e("orion", "----" + content);
Map<String, String> xml = decodeXml(content);
return xml;
}
@Override
protected void onPostExecute(Map<String, String> result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
resultunifiedorder = result;
handler.sendEmptyMessage(0);
}
}
/**
* 生成xml参数，用于生成预支付交易单，获取prepayId
* @param money
* @return
*/
private String getProductArgs(int money) {
StringBuffer xml = new StringBuffer();
try {
DecimalFormat df = new DecimalFormat("#");
String price = df.format(money * 100);
String nonceStr = getNonceStr();
xml.append("<xml>");
List<NameValuePair> packageParams = new LinkedList<NameValuePair>();
packageParams.add(new BasicNameValuePair("appid", WXKeys.WX_APPID));
packageParams.add(new BasicNameValuePair("body", "APP pay test"));
packageParams.add(new BasicNameValuePair("mch_id", WXKeys.WX_MCH_ID));
packageParams.add(new BasicNameValuePair("nonce_str", nonceStr));
packageParams.add(new BasicNameValuePair("notify_url", "http://www.baidu.com/"));//你自己的的回调地址！！！
packageParams.add(new BasicNameValuePair("out_trade_no", getOutTradeNo()));
packageParams.add(new BasicNameValuePair("total_fee", price));
packageParams.add(new BasicNameValuePair("trade_type", "APP"));
String sign = getPackageSign(packageParams);
packageParams.add(new BasicNameValuePair("sign", sign));
String xmlString = toXml(packageParams);
return xmlString;
} catch (Exception e) {
// TODO: handle exception
return null;
}
}
/**
* 获取支付参数
*/
private void getPayParameter() {
req.appId = WXKeys.WX_APPID;
req.partnerId = WXKeys.WX_MCH_ID;
if (resultunifiedorder != null) {
req.prepayId = resultunifiedorder.get("prepay_id");
} else {
Toast.makeText(mContext, "预支付交易单生成失败", Toast.LENGTH_SHORT).show();
}
req.packageValue = "Sign=WXPay";
req.nonceStr = getNonceStr();
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 = getPaySign(signParams);
}
/**
* 调起微信支付
*/
private void sendPayReq() {
iwxapi.registerApp(WXKeys.WX_APPID);
iwxapi.sendReq(req);
}
/**
* 生成随机数
* @return
*/
private String getNonceStr() {
// TODO Auto-generated method stub
Random random = new Random();
return getMessageDigest(String.valueOf(random.nextInt(10000)).getBytes());
}
/**
* 生成第一次签名
* @param params
* @return
*/
private String getPackageSign(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(WXKeys.WX_PRIVATE_KEY);
String packageSign = getMessageDigest(sb.toString().getBytes()).toUpperCase();
Log.e("Simon", ">>>>" + packageSign);
return packageSign;
}
/**
* 生成第二次签名
* @param params
* @return
*/
private String getPaySign(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(WXKeys.WX_PRIVATE_KEY);
String appSign = getMessageDigest(sb.toString().getBytes());
Log.e("Simon","----"+appSign);
return appSign;
}
/**
* 获取时间戳
*
* @return
*/
private static long genTimeStamp() {
return System.currentTimeMillis() / 1000;
}
/**
* 获取设备ip地址
* @return
*/
private static String getIpAddressString() {
try {
for (Enumeration<NetworkInterface> enNetI = NetworkInterface
.getNetworkInterfaces(); enNetI.hasMoreElements(); ) {
NetworkInterface netI = enNetI.nextElement();
for (Enumeration<InetAddress> enumIpAddr = netI
.getInetAddresses(); enumIpAddr.hasMoreElements(); ) {
InetAddress inetAddress = enumIpAddr.nextElement();
if (inetAddress instanceof Inet4Address && !inetAddress.isLoopbackAddress()) {
return inetAddress.getHostAddress();
}
}
}
} catch (SocketException e) {
e.printStackTrace();
}
return "127.0.0.1";
}
/**
* 获取外部订单号
*/
String getOutTradeNo() {
SimpleDateFormat format = new SimpleDateFormat("MMddHHmmss");
Date date = new Date();
String strKey = format.format(date);
java.util.Random r = new java.util.Random();
strKey = strKey + r.nextInt();
strKey = strKey.substring(0, 15);
return strKey;
}
/**
* 转换xml
* @param params
* @return
*/
private static 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("Simon", ">>>>" + sb.toString());
return sb.toString();
}
/**
* 转换xml
* @param content
* @return
*/
private 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("Simon", "----" + e.toString());
}
return null;
}
/**
* md5加密
*
* @param buffer
* @return
*/
private static String getMessageDigest(byte[] buffer) {
char hexDigits[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
try {
MessageDigest mdTemp = MessageDigest.getInstance("MD5");
mdTemp.update(buffer);
byte[] md = mdTemp.digest();
int j = md.length;
char str[] = new char[j * 2];
int k = 0;
for (int i = 0; i < j; i++) {
byte byte0 = md[i];
str[k++] = hexDigits[byte0 >>> 4 & 0xf];
str[k++] = hexDigits[byte0 & 0xf];
}
return new String(str);
} catch (Exception e) {
return null;
}
}
}
参考
大致的流程就如上面所说，其他没有提到的大多在官方demo中有。需要详细的过程可以参考下面两个两篇(感谢原作者)：
Android微信支付详解与Demo
详细介绍Android开发集成微信支付(二) --- 完整版本
