C#，微信小程序支付接口

it2023-05-27 68

最近有个项目涉及微信小程序支付功能，这里小墨将一些需要注意的地方已经实现步骤记录下来，给有需要的朋友

1、前期准备

需要提前准备好【全局变量】

public static string _appid = "xxxxxxxx";//appid public static string appsecret = "xxxxxxxxx";//小程序密钥 public static string _mch_id = "xxxxxx";//商户号 public static string _key = "xxxxxxxxxxxxxxx";//商户平台设置的密钥key

这里可以找公司要，一般会提供，自己开发的话可以去微信公众平台申请，入口： https://mp.weixin.qq.com

//模拟wx统一下单 openid(前台获取) public string getda(dynamic _) { wx_parameter req = this.Bind<wx_parameter>();//这里是小程序传递的参数 //支付费用 double total_fee =double.Parse(req.total_fee);//支付金额 //获取openid var authorizeList = xx.GetList(new { applet_token = token }.ToJson()).ToList(); var user = xxx.GetList(new { open_id = authorizeList[0].openid }.ToJson()).ToList()[0]; string openid = user.open_id; //获取openid的方法可以百度下，https://www.cnblogs.com/dujian123/p/11184781.html return Getprepay_id(_appid, "shanghaifendian", "monixiaofei", _mch_id, GetRandomString(30), "http://www.weixin.qq.com/wxpay/pay.php", openid, getRandomTime(), total_fee); }

获取openid：https://www.cnblogs.com/dujian123/p/11184781.html

/// <summary> /// 微信统一下单获取prepay_id & 再次签名返回数据 /// 屡一下思路：通过参数请求统一下单的链接，返回的xml解析后，判断成功后，进行二次签名，最终返回给小程序前端。 /// </summary> /// <param name="appid">appid</param> /// <param name="attach">附加数据(描述)</param> /// <param name="body">商品描述</param> /// <param name="mch_id">商户号</param> /// <param name="nonce_str">随机字符串，不长于32位。 </param> /// <param name="notify_url">通知地址</param> /// <param name="openid">openid</param> /// <param name="bookingNo">商户订单号</param> /// <param name="total_fee">支付金额单位为（分）比如一元等于100分</param> /// <returns></returns> private static string Getprepay_id(string appid, string attach, string body, string mch_id, string nonce_str, string notify_url, string openid, string bookingNo, double total_fee) { var url = "https://api.mch.weixin.qq.com/pay/unifiedorder";//微信统一下单请求地址 string strA = "appid=" + appid + "&attach=" + attach + "&body=" + body + "&mch_id=" + mch_id + "&nonce_str=" + nonce_str + "&notify_url=" + notify_url + "&openid=" + openid + "&out_trade_no=" + bookingNo + "&spbill_create_ip=61.50.221.43&total_fee=" + total_fee + "&trade_type=JSAPI"; string strk = strA + "&key=" + _key; //key为商户平台设置的密钥key(假) string strMD5 = MD5(strk).ToUpper();//MD5签名 //string strHash=HmacSHA256("sha256",strmd5).ToUpper(); //签名方式只需一种(MD5 或 HmacSHA256 【支付文档需仔细看】) //签名 //终端ip string spbill_create_ip = getspbill_create_ip(); var formData = "<xml>"; formData += "<appid>" + appid + "</appid>";//appid formData += "<attach>" + attach + "</attach>"; //附加数据(描述) formData += "<body>" + body + "</body>";//商品描述 formData += "<mch_id>" + mch_id + "</mch_id>";//商户号 formData += "<nonce_str>" + nonce_str + "</nonce_str>";//随机字符串，不长于32位。 formData += "<notify_url>" + notify_url + "</notify_url>";//通知地址 formData += "<openid>" + openid + "</openid>";//openid formData += "<out_trade_no>" + bookingNo + "</out_trade_no>";//商户订单号 --待 formData += "<spbill_create_ip>"+ spbill_create_ip + "</spbill_create_ip>";//终端IP --用户ip formData += "<total_fee>" + Convert.ToInt32(total_fee * 100).ToString() + "</total_fee>";//支付金额单位为（分） formData += "<trade_type>JSAPI</trade_type>";//交易类型(JSAPI--公众号支付) formData += "<sign>" + strMD5 + "</sign>"; //签名 formData += "</xml>"; //请求数据 var getdata = sendPost(url, formData); //获取xml数据 XmlDocument doc = new XmlDocument(); doc.LoadXml(getdata); wx w = new wx(); if (doc != null) { XmlNode xmlNode = doc["xml"]; if (xmlNode["return_code"].InnerText.Equals("SUCCESS") && xmlNode["result_code"].InnerText.Equals("SUCCESS")) { #region 再次签名 //时间戳 string _time = getTime().ToString(); //prepay_id string prepay_id = xmlNode["prepay_id"].InnerText; //再次签名返回数据至小程序 string strB = "appId=" + appid + "&nonceStr=" + nonce_str + "&package=prepay_id=" + prepay_id + "&signType=MD5&timeStamp=" + _time + "&key=" + _key; w.Result = "Success"; w.errmsg = "统一下单成功"; w.timeStamp = _time; w.nonceStr = nonce_str; w.package = "prepay_id=" + prepay_id; w.paySign = MD5(strB).ToUpper(); ; w.signType = "MD5"; //向小程序返回json数据 #endregion } else { w.Result = "Error"; w.errmsg = xmlNode["return_msg"].InnerText; } } else { w.Result = "Error"; w.errmsg ="统一下单失败"; } return JsonConvert.SerializeObject(w); }

生成随机字符串以及签名加密的方法可以参考下面

/// <summary> /// 生成随机串 /// </summary> /// <param name="length">字符串长度</param> /// <returns></returns> private static string GetRandomString(int length) { const string key = "ABCDEFGHJKLMNPQRSTUVWXYZ23456789"; if (length< 1) return string.Empty; Random rnd = new Random(); byte[] buffer = new byte[8]; ulong bit = 31; ulong result = 0; int index = 0; StringBuilder sb = new StringBuilder((length / 5 + 1) * 5); while (sb.Length<length) { rnd.NextBytes(buffer); buffer[5] = buffer[6] = buffer[7] = 0x00; result = BitConverter.ToUInt64(buffer, 0); while (result > 0 && sb.Length<length) { index = (int) (bit & result); sb.Append(key[index]); result = result >> 5; } } return sb.ToString(); } /// <summary> /// 获取终端ip,访问者ip /// </summary> /// <param name="_"></param> /// <returns></returns> private static string getspbill_create_ip() { string url = "https://pv.sohu.com/cityjson?ie=utf-8"; using (var httpClient = new HttpClient()) { httpClient.DefaultRequestHeaders.Add("Accept", "application/json");//设置请求头 var url1 = new Uri(url); // response var response = httpClient.GetAsync(url1).Result; var data = response.Content.ReadAsStringAsync().Result.Trim('"'); data = data.TrimEnd(';').Split('=')[1].ToString(); JObject obj = (JObject)JsonConvert.DeserializeObject(data); string spbill_create_ip = obj["cip"].ToString(); return spbill_create_ip; } } /// <summary> /// 获取时间戳，时间戳从1970年1月1日00:00:00至今的秒数,即当前的时间 /// </summary> /// <returns></returns> private static long getTime() { TimeSpan cha = (DateTime.Now - TimeZone.CurrentTimeZone.ToLocalTime(new System.DateTime(1970, 1, 1))); long t = (long)cha.TotalSeconds; return t; } /// <summary> /// MD5签名方法 /// </summary> /// <param name="inputText">加密参数</param> /// <returns></returns> private static string MD5(string inputText) { MD5 md5 = new MD5CryptoServiceProvider(); byte[] fromData = System.Text.Encoding.UTF8.GetBytes(inputText); byte[] targetData = md5.ComputeHash(fromData); string byte2String = null; for (int i = 0; i<targetData.Length; i++) { byte2String += targetData[i].ToString("x2"); } return byte2String; } /// <summary> /// HMAC-SHA256签名方式 /// </summary> /// <param name="message"></param> /// <param name="secret"></param> /// <returns></returns> private static string HmacSHA256(string message, string secret) { secret = secret ?? ""; var encoding = new System.Text.UTF8Encoding(); byte[] keyByte = encoding.GetBytes(secret); byte[] messageBytes = encoding.GetBytes(message); using (var hmacsha256 = new HMACSHA256(keyByte)) { byte[] hashmessage = hmacsha256.ComputeHash(messageBytes); return Convert.ToBase64String(hashmessage); } } /// <summary> /// wx统一下单请求数据 /// </summary> /// <param name="URL">请求地址</param> /// <param name="urlArgs">参数</param> /// <returns></returns> private static string sendPost(string URL, string urlArgs) { System.Net.WebClient wCient = new System.Net.WebClient(); wCient.Headers.Add("Content-Type", "application/x-www-form-urlencoded"); //byte[] postData = System.Text.Encoding.ASCII.GetBytes(urlArgs); 如果微信签名中有中文会签名失败　　　　　　byte[] postData = System.Text.Encoding.UTF8.GetBytes(urlArgs);　　　　　 byte[] responseData = wCient.UploadData(URL, "POST", postData); string returnStr = System.Text.Encoding.UTF8.GetString(responseData);//返回接受的数据 return returnStr; } /// <summary> /// 生成订单号【这里可以用一个订单表记录订单号】 /// </summary> /// <returns></returns> private static string getRandomTime() { Random rd = new Random();//用于生成随机数 string DateStr = DateTime.Now.ToString("yyyyMMddHHmmssMM");//日期 string str = DateStr + rd.Next(10000).ToString().PadLeft(4, '0');//带日期的随机数 return str; }

下面是所需要的实体类：

/// <summary> /// 小程序调用后台 /// </summary> public class wx_parameter { /// <summary> /// 支付费用 /// </summary> public string total_fee { get; set; } } /// <summary> /// 返回给小程序 /// </summary> public class wx { /// <summary> /// 返回结果【Success/Error】 /// </summary> public string Result { get; set; } /// <summary> /// 描述 /// </summary> public string errmsg { get; set; } /// <summary> /// 时间戳 /// </summary> public string timeStamp { get;set;} /// <summary> /// 随机数 /// </summary> public string nonceStr { get; set; } /// <summary> /// 同一下单接口的prepay_id参数 /// </summary> public string package { get; set; } /// <summary> /// 第二次签名 /// </summary> public string paySign { get; set; } /// <summary> /// 签名方式 /// </summary> public string signType { get; set; } }

最后需要做一个回调，用于支付成功后修改订单号状态等等（根据自己业务需求来）

下面是一些参考文档：

《微信官方文档：支付部分》

https://pay.weixin.qq.com/wiki/doc/api/wxa/wxa_api.php?chapter=3_1

《微信官方文档：统一支付》

https://pay.weixin.qq.com/wiki/doc/api/wxa/wxa_api.php?chapter=9_1

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