微信app支付android客户端以及.net服务端实现

由于公司运营需要，需要在客户端(android/ios)增加微信以及支付宝支付，在调用微信app支付时遇到一些问题，也算是一些踩过的坑，记录下来

，希望能对.net开发者服务端网站更快的集成微信app支付。

1.开发所需资料：微信开放平台应用的appid以及appsecert,商户平台的商户号以及api安全里面里面设置的key，详见 微信支付账户相关信息;

2.微信开发者平台完善应用平台的相关信息,android应用签名必须用打包签名过的发布版本apk(这一步很重用)，包名必须一致，可以用微信提供的签名工具获得,签名工具下载地址https://open.weixin.qq.com/zh_CN/htmledition/res/dev/download/sdk/Gen_Signature_Android.apk

以下是交互时序图，统一下单API、支付结果通知API和查询订单API等都涉及签名过程，调用都必须在商户服务器端完成(来源微信支付开发文档):

商户系统和微信支付支付系统主要交互:

步骤1：用户在商户APP中选择商品，提交订单，选择微信支付。商户后台收到订单时需要调用微信的同意下单接口，生成预支付单;

C#大概代码如下（相关代码参考自JeffreySu/WeiXinMPSDK ）:

private WechatPayResult generatePayResult(string mchappid,string mchid
            ,string body,string orderno,int total,string ip,string notify,string mchkey,string nonce)
        {
            DateTime start = DateTime.Now,end= DateTime.Now.AddMinutes(15);
            var xmlDataInfo = new TenPayV3UnifiedorderRequestData(mchappid
               ,mchid, body, orderno, total
               ,ip,notify, TenPayV3Type.APP
               , null, mchkey, nonce, null,start,end);
            var result = TenPayV3.Unifiedorder(xmlDataInfo);//调用统一订单接口
            return new WechatPayResult
            {
                appid=mchappid,
                body=body,
                CreatedOn=DateTime.Now,
                mch_id=mchid,
                prepay_id=result.prepay_id,
                spbill_create_ip=ip,
                nonce_str=nonce,
                timeStamp= TenPayV3Util.GetTimestamp(),
                out_trade_no=orderno,
                time_start=start,
                time_expire=end,
                total_fee=total,
                trade_type=result.trade_type
            };
        }

  public class RequestHandler
    {

        public RequestHandler()
        {
            Parameters = new Hashtable();
        }


        public RequestHandler(HttpContext httpContext)
        {
            Parameters = new Hashtable();

            this.HttpContext = httpContext ?? HttpContext.Current;

        }
        /// <summary>
        /// 密钥
        /// </summary>
        private string Key;

        protected HttpContext HttpContext;

        /// <summary>
        /// 请求的参数
        /// </summary>
        protected Hashtable Parameters;

        /// <summary>
        /// debug信息
        /// </summary>
        private string DebugInfo;

        /// <summary>
        /// 初始化函数
        /// </summary>
        public virtual void Init()
        {
        }
        /// <summary>
        /// 获取debug信息
        /// </summary>
        /// <returns></returns>
        public String GetDebugInfo()
        {
            return DebugInfo;
        }
        /// <summary>
        /// 获取密钥
        /// </summary>
        /// <returns></returns>
        public string GetKey()
        {
            return Key;
        }
        /// <summary>
        /// 设置密钥
        /// </summary>
        /// <param name="key"></param>
        public void SetKey(string key)
        {
            this.Key = key;
        }

        /// <summary>
        /// 设置参数值
        /// </summary>
        /// <param name="parameter"></param>
        /// <param name="parameterValue"></param>
        public void SetParameter(string parameter, string parameterValue)
        {
            if (parameter != null && parameter != "")
            {
                if (Parameters.Contains(parameter))
                {
                    Parameters.Remove(parameter);
                }

                Parameters.Add(parameter, parameterValue);
            }
        }


        /// <summary>
        /// 当参数不为null或空字符串时，设置参数值
        /// </summary>
        /// <param name="parameter"></param>
        /// <param name="parameterValue"></param>
        public void SetParameterWhenNotNull(string parameter, string parameterValue)
        {
            if (!string.IsNullOrEmpty(parameterValue))
            {
                SetParameter(parameter, parameterValue);
            }
        }

        /// <summary>
        /// 创建md5摘要,规则是:按参数名称a-z排序,遇到空值的参数不参加签名
        /// </summary>
        /// <param name="key">参数名</param>
        /// <param name="value">参数值</param>
        /// key和value通常用于填充最后一组参数
        /// <returns></returns>
        public virtual string CreateMd5Sign(string key, string value)
        {
            StringBuilder sb = new StringBuilder();

            ArrayList akeys = new ArrayList(Parameters.Keys);
            akeys.Sort();

            foreach (string k in akeys)
            {
                string v = (string)Parameters[k];
                if (null != v && "".CompareTo(v) != 0
                    && "sign".CompareTo(k) != 0 
                    //&& "sign_type".CompareTo(k) != 0
                    && "key".CompareTo(k) != 0)
                {
                    sb.Append(k + "=" + v + "&");
                }
            }

            sb.Append(key + "=" + value);
            string sign = EncryptHelper.GetMD5(sb.ToString(), GetCharset()).ToUpper();
            //string sign = MD5UtilHelper.GetMD5(sb.ToString(), GetCharset()).ToUpper();
            return sign;
        }
        public virtual string CreateMd5Sign()
        {
            StringBuilder sb = new StringBuilder();

            ArrayList akeys = new ArrayList(Parameters.Keys);
            akeys.Sort();

            foreach (string k in akeys)
            {
                string v = (string)Parameters[k];
                if (null != v && "".CompareTo(v) != 0
                    && "sign".CompareTo(k) != 0
                    //&& "sign_type".CompareTo(k) != 0
                    && "key".CompareTo(k) != 0)
                {
                    sb.Append(k + "=" + v + "&");
                }
            }
            string sign = EncryptHelper.GetMD5(sb.ToString().Substring(0,sb.Length-1), GetCharset()).ToUpper();
            return sign;
        }
        /// <summary>
        /// 输出XML
        /// </summary>
        /// <returns></returns>
        public string ParseXML()
        {
            StringBuilder sb = new StringBuilder();
            sb.Append("<xml>");
            foreach (string k in Parameters.Keys)
            {
                string v = (string)Parameters[k];
                if (v != null && Regex.IsMatch(v, @"^[0-9.]$"))
                {

                    sb.Append("<" + k + ">" + v + "</" + k + ">");
                }
                else
                {
                    sb.Append("<" + k + "><![CDATA[" + v + "]]></" + k + ">");
                }

            }
            sb.Append("</xml>");
            return sb.ToString();
        }



        /// <summary>
        /// 设置debug信息
        /// </summary>
        /// <param name="debugInfo"></param>
        public void SetDebugInfo(String debugInfo)
        {
            this.DebugInfo = debugInfo;
        }

        public Hashtable GetAllParameters()
        {
            return this.Parameters;
        }

        protected virtual string GetCharset()
        {
            if (this.HttpContext == null)
            {
                return Encoding.UTF8.BodyName;
            }

            return this.HttpContext.Request.ContentEncoding.BodyName;
        }
    }

 /// <summary>
    /// 微信支付提交的XML Data数据[统一下单]
    /// </summary>
    public class TenPayV3UnifiedorderRequestData
    {
        /// <summary>
        /// 公众账号ID
        /// </summary>
        public string AppId { get; set; }
        /// <summary>
        /// 商户号
        /// </summary>
        public string MchId { get; set; }
        /// <summary>
        /// 自定义参数，可以为终端设备号(门店号或收银设备ID)，PC网页或公众号内支付可以传"WEB"，String(32)如：013467007045764
        /// </summary>
        public string DeviceInfo { get; set; }
        /// <summary>
        /// 随机字符串
        /// </summary>
        public string NonceStr { get; set; }
        /// <summary>
        /// 签名类型，默认为MD5，支持HMAC-SHA256和MD5。（使用默认）
        /// </summary>
        public string SignType { get; set; }
        /// <summary>
        /// 商品信息
        /// </summary>
        public string Body { get; set; }
        /// <summary>
        /// 商品详细列表，使用Json格式，传输签名前请务必使用CDATA标签将JSON文本串保护起来。
        ///cost_price Int 可选 32 订单原价，商户侧一张小票订单可能被分多次支付，订单原价用于记录整张小票的支付金额。当订单原价与支付金额不相等则被判定为拆单，无法享/受/优/惠。
        /// receipt_id String 可选 32 商家小票ID
        ///goods_detail 服务商必填[]：
        ///└ goods_id String 必填 32 商品的编号
        ///└ wxpay_goods_id String 可选 32 微信支付定义的统一商品编号
        ///└ goods_name String 可选 256 商品名称 
        ///└ quantity Int 必填  32 商品数量
        ///└ price Int 必填 32 商品单价，如果商户有优惠，需传输商户优惠后的单价
        ///注意：单品总金额应&lt;=订单总金额total_fee，否则会无法享受优惠。
        /// String(6000)
        /// </summary>
        public string Detail { get; set; }
        /// <summary>
        /// 附加数据，在查询API和支付通知中原样返回，可作为自定义参数使用。String(127)，如：深圳分店
        /// </summary>
        public string Attach { get; set; }
        /// <summary>
        /// 符合ISO 4217标准的三位字母代码，默认人民币：CNY，详细列表请参见货币类型。String(16)，如：CNY
        /// </summary>
        public string FeeType { get; set; }
        /// <summary>
        /// 商家订单号
        /// </summary>
        public string OutTradeNo { get; set; }
        /// <summary>
        /// 商品金额,以分为单位(money * 100).ToString()
        /// </summary>
        public int TotalFee { get; set; }
        /// <summary>
        /// 用户的公网ip，不是商户服务器IP
        /// </summary>
        public string SpbillCreateIP { get; set; }
        /// <summary>
        /// 订单生成时间，最终生成格式为yyyyMMddHHmmss，如2009年12月25日9点10分10秒表示为20091225091010。其他详见时间规则。
        /// 如果为空，则默认为当前服务器时间
        /// </summary>
        public string TimeStart { get; set; }
        /// <summary>
        /// 订单失效时间，格式为yyyyMMddHHmmss，如2009年12月27日9点10分10秒表示为20091227091010。其他详见时间规则
        /// 注意：最短失效时间间隔必须大于5分钟。
        /// 留空则不设置失效时间
        /// </summary>
        public string TimeExpire { get; set; }
        /// <summary>
        /// 商品标记，使用代金券或立减优惠功能时需要的参数，说明详见代金券或立减优惠。String(32)，如：WXG
        /// </summary>
        public string GoodsTag { get; set; }
        /// <summary>
        /// 接收财付通通知的URL
        /// </summary>
        public string NotifyUrl { get; set; }
        /// <summary>
        /// 交易类型
        /// </summary>
        public TenPayV3Type TradeType { get; set; }
        /// <summary>
        /// trade_type=NATIVE时（即扫码支付），此参数必传。此参数为二维码中包含的商品ID，商户自行定义。
        /// String(32)，如：12235413214070356458058
        /// </summary>
        public string ProductId { get; set; }
        /// <summary>
        /// 上传此参数no_credit--可限制用户不能使用信用卡支付
        /// </summary>
        public string LimitPay { get; set; }
        /// <summary>
        /// 用户的openId
        /// </summary>
        public string OpenId { get; set; }

        /// <summary>
        /// 
        /// </summary>
        public string Key { get; set; }

        public readonly RequestHandler PackageRequestHandler;
        public readonly string Sign;

        /// <summary>
        /// 
        /// </summary>
        /// <param name="appId"></param>
        /// <param name="mchId"></param>
        /// <param name="body"></param>
        /// <param name="outTradeNo"></param>
        /// <param name="totalFee">单位：分</param>
        /// <param name="spbillCreateIp"></param>
        /// <param name="notifyUrl"></param>
        /// <param name="tradeType"></param>
        /// <param name="openid"></param>
        /// <param name="key"></param>
        /// <param name="nonceStr"></param>
        /// <param name="deviceInfo">自定义参数，可以为终端设备号(门店号或收银设备ID)，PC网页或公众号内支付可以传"WEB"，String(32)如：013467007045764</param>
        /// <param name="timeStart">订单生成时间，如果为空，则默认为当前服务器时间</param>
        /// <param name="timeExpire">订单失效时间，留空则不设置失效时间</param>
        /// <param name="detail">商品详细列表</param>
        /// <param name="attach">附加数据</param>
        /// <param name="feeType">符合ISO 4217标准的三位字母代码，默认人民币：CNY</param>
        /// <param name="goodsTag">商品标记，使用代金券或立减优惠功能时需要的参数，说明详见代金券或立减优惠。String(32)，如：WXG</param>
        /// <param name="productId">trade_type=NATIVE时（即扫码支付），此参数必传。此参数为二维码中包含的商品ID，商户自行定义。String(32)，如：12235413214070356458058</param>
        /// <param name="limitPay">是否限制用户不能使用信用卡支付</param>
        public TenPayV3UnifiedorderRequestData(string appId, string mchId, string body, string outTradeNo, int totalFee, string spbillCreateIp,
            string notifyUrl, TenPayV3Type tradeType, string openid, string key, string nonceStr,
            string deviceInfo = null, DateTime? timeStart = null, DateTime? timeExpire = null,
           string detail = null, string attach = null, string feeType = "CNY", string goodsTag = null, string productId = null, bool limitPay = false)
        {
            AppId = appId;
            MchId = mchId;
            DeviceInfo = deviceInfo;
            NonceStr = nonceStr;
            SignType = "MD5";
            Body = body ?? "";
            Detail = detail;
            Attach = attach;
            OutTradeNo = outTradeNo;
            FeeType = feeType;
            TotalFee = totalFee;
            SpbillCreateIP = spbillCreateIp;
            TimeStart = (timeStart ?? DateTime.Now).ToString("yyyyMMddHHmmss");
            TimeExpire = timeExpire.HasValue ? timeExpire.Value.ToString("yyyyMMddHHmmss") : null;
            GoodsTag = goodsTag;
            NotifyUrl = notifyUrl;
            TradeType = tradeType;
            ProductId = productId;
            LimitPay = limitPay ? "no_credit" : null;
            OpenId = openid;
            Key = key;

            #region 设置RequestHandler

            //创建支付应答对象
            PackageRequestHandler = new RequestHandler(null);
            //初始化
            PackageRequestHandler.Init();

            //设置package订单参数
            //以下设置顺序按照官方文档排序，方便维护：https://pay.weixin.qq.com/wiki/doc/api/jsapi.php?chapter=9_1
            PackageRequestHandler.SetParameter("appid", this.AppId);                       //公众账号ID
            PackageRequestHandler.SetParameter("mch_id", this.MchId);                      //商户号
            PackageRequestHandler.SetParameterWhenNotNull("device_info", this.DeviceInfo); //自定义参数
            PackageRequestHandler.SetParameter("nonce_str", this.NonceStr);                //随机字符串
            PackageRequestHandler.SetParameterWhenNotNull("sign_type", this.SignType);     //签名类型，默认为MD5
            PackageRequestHandler.SetParameter("body", this.Body);                         //商品信息
            PackageRequestHandler.SetParameterWhenNotNull("detail", this.Detail);          //商品详细列表
            PackageRequestHandler.SetParameterWhenNotNull("attach", this.Attach);          //附加数据
            PackageRequestHandler.SetParameter("out_trade_no", this.OutTradeNo);           //商家订单号
            PackageRequestHandler.SetParameterWhenNotNull("fee_type", this.FeeType);       //符合ISO 4217标准的三位字母代码，默认人民币：CNY
            PackageRequestHandler.SetParameter("total_fee", this.TotalFee.ToString());  //商品金额,以分为单位(money * 100).ToString()
            PackageRequestHandler.SetParameter("spbill_create_ip", this.SpbillCreateIP);   //用户的公网ip，不是商户服务器IP
            PackageRequestHandler.SetParameterWhenNotNull("time_start", this.TimeStart);   //订单生成时间
            PackageRequestHandler.SetParameterWhenNotNull("time_expire", this.TimeExpire);  //订单失效时间
            PackageRequestHandler.SetParameterWhenNotNull("goods_tag", this.GoodsTag);     //商品标记
            PackageRequestHandler.SetParameter("notify_url", this.NotifyUrl);              //接收财付通通知的URL
            PackageRequestHandler.SetParameter("trade_type", this.TradeType.ToString());   //交易类型
            PackageRequestHandler.SetParameterWhenNotNull("product_id", this.ProductId);   //trade_type=NATIVE时（即扫码支付），此参数必传。
            PackageRequestHandler.SetParameterWhenNotNull("limit_pay", this.LimitPay);     //上传此参数no_credit--可限制用户不能使用信用卡支付
            PackageRequestHandler.SetParameter("openid", this.OpenId);          //用户的openId，trade_type=JSAPI时（即公众号支付），此参数必传
            Sign = PackageRequestHandler.CreateMd5Sign("key", this.Key);
            PackageRequestHandler.SetParameter("sign", Sign);                              //签名
            #endregion
        }
    }

 /// <summary>
        /// 统一支付接口
        /// 统一支付接口，可接受JSAPI/NATIVE/APP 下预支付订单，返回预支付订单号。NATIVE 支付返回二维码code_url。
        /// </summary>
        /// <param name="dataInfo">微信支付需要post的Data数据</param>
        /// <param name="timeOut"></param>
        /// <returns></returns>
        public static UnifiedorderResult Unifiedorder(TenPayV3UnifiedorderRequestData dataInfo, int timeOut = Config.TIME_OUT)
        {
            var urlFormat = "https://api.mch.weixin.qq.com/pay/unifiedorder";
            var data = dataInfo.PackageRequestHandler.ParseXML();//获取XML
            //throw new Exception(data.HtmlEncode());
            MemoryStream ms = new MemoryStream();
            var formDataBytes = data == null ? new byte[0] : Encoding.UTF8.GetBytes(data);
            ms.Write(formDataBytes, 0, formDataBytes.Length);
            ms.Seek(0, SeekOrigin.Begin);//设置指针读取位置

            var resultXml = RequestUtility.HttpPost(urlFormat, null, ms, timeOut: timeOut);
            return new UnifiedorderResult(resultXml);
        }

步骤2：统一下单接口返回正常的prepay_id，再按签名规范重新生成签名后，将数据传输给APP。参与签名的字段名为appId，partnerId，prepayId，nonceStr，timeStamp，package。注意：package的值格式为Sign=WXPay,签名的字段数量必须跟你app调起微信支付所传的参数一致:

 /// <summary>
        /// 生成微信app支付前面
        /// </summary>
        /// <param name="appId"></param>
        /// <param name="timeStamp"></param>
        /// <param name="nonceStr"></param>
        /// <param name="package"></param>
        /// <param name="key"></param>
        /// <param name="partnerid"></param>
        /// <param name="prepayid"></param>
        /// <param name="signType"></param>
        /// <returns></returns>
        public static string GetAppPaySign(string appId
            , string timeStamp, string nonceStr, string package,
            string key,string partnerid,string prepayid,string signType = "MD5"
            )
        {
            RequestHandler paySignReqHandler = new RequestHandler(null);
            paySignReqHandler.SetParameter("appid", appId.Trim());
            paySignReqHandler.SetParameter("timestamp", timeStamp.Trim());
            paySignReqHandler.SetParameter("noncestr", nonceStr.Trim());
            paySignReqHandler.SetParameter("partnerid", partnerid);
            paySignReqHandler.SetParameter("prepayid", prepayid);
            paySignReqHandler.SetParameter("package", package.Trim());
            //paySignReqHandler.SetParameter("signtype", "MD5");
            var paySign = paySignReqHandler.CreateMd5Sign("key", key);
            return paySign;
        }

步骤3：商户APP调起微信支付。详细介绍参见微信支付官方文档

关键代码如下:

 public   static  IWXAPI api;
api= WXAPIFactory.createWXAPI(this, Constants.APP_ID,true);
        api.registerApp(Constants.APP_ID); 
Result result = JSON.parseObject(bytes, Result.class);
                    if (null != result) {
                        if (result.isSuccess()) {
                            prepay prepay = JSON.parseObject(result.getData().toString(), prepay.class);
                            PayReq request = new PayReq();
                            request.appId = prepay.getAppid();
                            request.partnerId =prepay.getPartnerid();
                            request.prepayId= prepay.getPrepayid();
                            request.packageValue = prepay.getPackages();
                            request.nonceStr= prepay.getNoncestr();
                            request.timeStamp=prepay.getTimestamp();
                            request.sign= prepay.getSign();
                            api.sendReq(request);
                        }
                    }

其中result.getData()表示服务端返回的预支付订单的相关参数，用这参数调用微信支付,该activity必须实现接口IWXAPIEventHandler，并实现

@Override
public void onResp(BaseResp baseResp) {
    if(baseResp.getType()== ConstantsAPI.COMMAND_PAY_BY_WX){
        Log.d("dd","onPayFinish,errCode="+baseResp.errCode);
    }
}
用于判断微信支付结果，安全起见，建议微信app回调后请求商户api相关接口确定支付结果
支付成功时微信后台会请求生成预支付单时传递的通知url（即payProvider.TenpayNotify）通知商户支付结果，商户后台校验相关信息

 [AllowAnonymous]
        public ActionResult PayResult()
        {
            ResponseHandler resHandler = new ResponseHandler(null);
            string return_code = resHandler.GetParameter("return_code");
            string return_msg = resHandler.GetParameter("return_msg");
            string res = null;
            EngineContext.Current.Resolve<ILogger>().Information("收到微信支付通知"+resHandler.ParseXML());
            //EngineContext.Current.Resolve<ILoggingService>().Write(LogType.Pay, resHandler.ParseXML());
            string orderno = resHandler.GetParameter("out_trade_no");
            string payno = resHandler.GetParameter("transaction_id");
            string nonce_str = resHandler.GetParameter("nonce_str");
            var order = _wechatService.GetWechatPayResult(orderno);
            if (order != null)
            {
                var first = order.FirstOrDefault(r => r.nonce_str == nonce_str);
                if (first != null)
                {
                    var payProvider = _wechatService.GetWechatPayProvider(first.appid);
                    resHandler.SetKey(payProvider.MchKey);
                        if (resHandler.IsTenpaySign())
                        {
                            if (return_code == TenPayTypeResult.SUCCESS.ToString())
                            {
                                int totaled= int.Parse(resHandler.GetParameter("total_fee"));
                                if (totaled == first.total_fee)
                                {
                                    first.IsSuccess = true;
                                    first.time_end = DateTime.Now;
                                    first.total_fee_ed = int.Parse(resHandler.GetParameter("total_fee"));
                                    first.transaction_id = payno;
                                    first.Content = resHandler.ParseXML();
                                    _wechatService.UpdateWechatPayResult(first);
                                    EngineContext.Current.Resolve<IEventPublisher>().Publish(resultEvent);
                                }else
                                {
                                    EngineContext.Current.Resolve<ILogger>().Information("微信支付金额与订单金额不匹配" + resHandler.ParseXML());
                                }
                                
                            }
                }
            }
            
            //验证请求是否从微信发过来（安全）
            string xml = string.Format(@"<xml>
   <return_code><![CDATA[{0}]]></return_code>
   <return_msg><![CDATA[{1}]]></return_msg>
</xml>", return_code, return_msg);
            return Content(xml, "text/xml");
        }

微信支付官方文档

微信.NET集成可参考现有轮子 JeffreySu/WeiXinMPSDK