.net 后台如何模拟http请求获取微信接口的AccessToken（基础支持）

1、首先你需要要公众号的key（Appid）,value(AppSecret) ,这是公众号的唯一凭证

1）登录公众号（服务号）

2）开发-->基本设置-->公众号的Appid,AppSecret信息

 3）Appsecret需要自己重置后记住密码，页面不显示

2、由于现在微信第三方接口比较严格，需要在公众号加上调用方的IP到白名单中

1）开发-->基本设置-->IP白名单

添加上调用方的IP地址（143.123.21.2），如：不加上IP地址，调用accesstoken接口会失败

 3、调用获取公众号基础支持的accessToken

1）添加http请求的辅助方法

        /// <summary>
        /// 后台发送POST请求
        /// </summary>
        /// <param name="url">服务器地址</param>
        /// <param name="data">发送的数据</param>
        /// <returns></returns>
        public string HttpPost(string url, string data)
        {
            try
            {
                //创建post请求
                HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
                request.Method = "POST";
                request.ContentType = "application/json;charset=UTF-8";
                byte[] payload = Encoding.UTF8.GetBytes(data);
                request.ContentLength = payload.Length;

                //发送post的请求
                Stream writer = request.GetRequestStream();
                writer.Write(payload, 0, payload.Length);
                writer.Close();

                //接受返回来的数据
                HttpWebResponse response = (HttpWebResponse)request.GetResponse();
                Stream stream = response.GetResponseStream();
                StreamReader reader = new StreamReader(stream, Encoding.UTF8);
                string value = reader.ReadToEnd();

                reader.Close();
                stream.Close();
                response.Close();

                return value;
            }
            catch (Exception)
            {
                return "";
            }
        }

        /// <summary>
        /// 后台发送GET请求
        /// </summary>
        /// <param name="url">服务器地址</param>
        /// <param name="data">发送的数据</param>
        /// <returns></returns>
        public string HttpGet(string url, string data)
        {
            try
            {
                //创建Get请求
                url = url + (data == "" ? "" : "?") + data;
                HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
                request.Method = "GET";
                request.ContentType = "text/html;charset=UTF-8";

                //接受返回来的数据
                HttpWebResponse response = (HttpWebResponse)request.GetResponse();
                Stream stream = response.GetResponseStream();
                StreamReader streamReader = new StreamReader(stream, Encoding.GetEncoding("utf-8"));
                string retString = streamReader.ReadToEnd();

                streamReader.Close();
                stream.Close();
                response.Close();

                return retString;
            }
            catch (Exception)
            {
                return "";
            }
        }

2）调用获取的后台方法

        /// <summary>
        /// 获取基础支持的accessToken
        /// </summary>
        /// <param name="appid">公众号凭证ID</param>
        /// <param name="secret">公众号凭证密码</param>
        /// <returns></returns>
        public string GetBaseAcccessToken(string appid, string secret)
        {
            string accessToken = string.Empty;

            string reqUrl = string.Format(@"https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid={0}&secret={1}", appid, secret);
            string resultStr = HttpGet(reqUrl,"");
            dynamic data = JsonConvert.DeserializeObject(resultStr);
            if (data["access_token"] != null)
            {
                accessToken = data["access_token"].ToString();
            }
            else
            {
                accessToken = "";
            }
            return accessToken;
        }

3）调用后返回的结果

3.1）成功

{
    "access_token": "35_4KxKJBhXFcRI7uM6FBixvZNDP7pPQuGK-AFsydgmGR3P4z9itSLvQlNmW8tYkOoOkGB_gb2P-VekacJnoMXghUwIRWQzSDMXyiIIouBtk06zPpQ0ddJ8O-5BjLM0PZArnJjsixN2kx1gcF_iJZDaAEADTX", 
    "expires_in": 7200
}

3.2）失败（未加入IP白名单）

{
    "errcode": 40164, 
    "errmsg": "invalid ip 113.111.4.104, not in whitelist"
}