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，
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：
/// <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 + "¬ify_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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