個人認為百度地圖開放平臺確實很好用但就是C#的SN校驗會出現以下幾個問題

一、官方的示例代碼說的不清不楚

獲取SN函數的Uri應該使用不帶功能變數名稱的Uri

比如：最終請求地址為https://api.map.baidu.com/location/ip?ip=119.126.10.15&coor=gcj02&ak=123456&sn=654321時
AKSNCaculater.CaculateAKSN中的uri參數應該使用https://api.map.baidu.com/location/ip?ip=119.126.10.15&coor=gcj02&ak=123456&sn=654321，而不可以是https://aspi.map.baidu.com/location/ip?coor=gcj02&ip=119.126.10.15&ak=123456&sn=654321

獲取SN的時候參數的順序是怎麼樣的，發送請求的時候參數的順序就必須是怎麼樣

比如：獲取SN的時候參數順序是ip=119.126.10.15&coor=gcj02&ak=123456，那麼最終請求地址就應該是https://api.map.baidu.com/location/ip?ip=119.126.10.15&coor=gcj02&ak=123456&sn=654321，而不可以是https://aspi.map.baidu.com/location/ip?coor=gcj02&ip=119.126.10.15&ak=123456&sn=654321

無論如何SN必須在最終請求地址的最後！

比如以上情況下：https://api.map.baidu.com/location/ip?ip=119.126.10.15&coor=gcj02&sn=654321&ak=123456就是一個錯誤的地址

二、官方MD5加密是錯的！

這一個真是把我害慘了，折騰了半天終於發現正確代碼（我也是copy別人的，但不管怎麼說，官方的MD5加密代碼確實是錯的）

正確的加密過程如下

public static string MD52(string password)
        {
            try
            {
                System.Security.Cryptography.HashAlgorithm hash = System.Security.Cryptography.MD5.Create();
                byte[] hash_out = hash.ComputeHash(System.Text.Encoding.UTF8.GetBytes(password));
 
                var md5_str = BitConverter.ToString(hash_out).Replace("-", "");
                return md5_str.ToLower();
 
            }
            catch
            {
 
                throw;
            }
        }

　　完整類如下：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
 
namespace SATPlatform
{
 
    public class AKSNCaculater
    {
        public static string MD52(string password)
        {
            try
            {
                System.Security.Cryptography.HashAlgorithm hash = System.Security.Cryptography.MD5.Create();
                byte[] hash_out = hash.ComputeHash(System.Text.Encoding.UTF8.GetBytes(password));
 
                var md5_str = BitConverter.ToString(hash_out).Replace("-", "");
                return md5_str.ToLower();
 
            }
            catch
            {
 
                throw;
            }
        }
 
        public static string MD5(string password)
        {
            byte[] textBytes = System.Text.Encoding.UTF8.GetBytes(password);
            try
            {
                System.Security.Cryptography.MD5CryptoServiceProvider cryptHandler;
                cryptHandler = new System.Security.Cryptography.MD5CryptoServiceProvider();
                byte[] hash = cryptHandler.ComputeHash(textBytes);
                string ret = "";
                foreach (byte a in hash)
                {
                    ret += a.ToString("x");
                }
                return ret;
            }
            catch
            {
                throw;
            }
        }
 
        public static string UrlEncode(string str)
        {
            str = System.Web.HttpUtility.UrlEncode(str);
            byte[] buf = Encoding.ASCII.GetBytes(str);//等同於Encoding.ASCII.GetBytes(str)
            for (int i = 0; i < buf.Length; i++)
                if (buf[i] == '%')
                {
                    if (buf[i + 1] >= 'a') buf[i + 1] -= 32;
                    if (buf[i + 2] >= 'a') buf[i + 2] -= 32;
                    i += 2;
                }
            return Encoding.ASCII.GetString(buf);//同上，等同於Encoding.ASCII.GetString(buf)
        }
 
        public static string HttpBuildQuery(IDictionary<string, string> querystring_arrays)
        {
 
            StringBuilder sb = new StringBuilder();
            foreach (var item in querystring_arrays)
            {
                sb.Append(UrlEncode(item.Key));
                sb.Append("=");
                sb.Append(UrlEncode(item.Value));
                sb.Append("&");
            }
            sb.Remove(sb.Length - 1, 1);
            return sb.ToString();
        }
 
        public static string CaculateAKSN(string ak, string sk, string url, IDictionary<string, string> querystring_arrays)
        {
            var queryString = HttpBuildQuery(querystring_arrays);
 
            var str = UrlEncode(url + "?" + queryString + sk);
 
            return MD52(str);
        }
    }
}

以上就是我被坑的經歷，希望對其他人有用~~~

最後再附帶上我的請求代碼

        /// <summary>
        /// 返回指定IP的位置對應的百度城市代碼（利用百度地圖API
        /// </summary>
        /// <param name="IP">需要查詢的IP地址</param>
        /// <returns></returns>
        public string GetPlace(string IP)
        {
            DataTable BasicIn = Reader("SELECT Th_MapAK , Th_MapSK FROM S_Inf");
            Dictionary<string, string> P = new Dictionary<string, string>()
            {
                {"ip",IP },
                {"coor","gcj02" },
                {"ak",BasicIn.Rows[0]["Th_MapAK"].ToString() }
                //{"address","百度大廈" },
                //{"output","json" },
                //{"ak","yourak" }
            };
            string GetSN = AKSNCaculater.CaculateAKSN(BasicIn.Rows[0]["Th_MapAK"].ToString(), BasicIn.Rows[0]["Th_MapSK"].ToString(), "/location/ip", P);
            //string GetSN = AKSNCaculater.CaculateAKSN("yourak", "yoursk", "/geocoder/v2/", P);
            HttpWebRequest NewRequest = (HttpWebRequest)WebRequest.Create("https://api.map.baidu.com/location/ip?" + AKSNCaculater.HttpBuildQuery(P) + "&sn=" + GetSN);
            NewRequest.Headers.Add("charset", "utf-8");
            NewRequest.Method = "GET";
            NewRequest.ContentType = "application/json";
            NewRequest.UserAgent = "Windows KeHuDuan";
            NewRequest.Timeout = 5000;//設置超時時間
            HttpWebResponse Response = (HttpWebResponse)NewRequest.GetResponse();
            Stream ResponseStream = Response.GetResponseStream();
            StreamReader ResponseStreamReader = new StreamReader(ResponseStream);
            string Res = ResponseStreamReader.ReadToEnd();
            ResponseStreamReader.Close();
            ResponseStream.Close();
            JObject ResJ = new JObject();
            try
            { ResJ = JObject.Parse(Res); }
            catch (Exception)
            { GiveErr(ErrCode.ThirdPartyError); }
            if (ResJ["status"].ToString() != "0")
                GiveErr(ErrCode.ThirdPartyError);
            return ResJ["content"]["address_detail"]["city_code"].ToString();
        }