C#请求WebApi

    public static class RequestService
    {
        public static string jwttoken = "Api验证权限需要的秘钥";

        /// <summary>
        /// GET请求
        /// </summary>
        /// <param name="url">请求地址</param>
        /// <param name="timeout">超时时间，默认为60000毫秒（1分钟）</param>
        /// <returns></returns>
        public static string GetHttpResponse(string url, int timeout = 60000)
        {

            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            request.Method = "GET";
            request.ContentType = "text/html;charset=UTF-8";
            request.UserAgent = null;
            request.Timeout = timeout;

            //往头部加入自定义验证信息
            SetHeaderValue(request.Headers, "Authorization", jwttoken);
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            Stream myResponseStream = response.GetResponseStream();
            StreamReader myStreamReader = new StreamReader(myResponseStream, Encoding.GetEncoding("utf-8"));
            string retString = myStreamReader.ReadToEnd();
            myStreamReader.Close();
            myResponseStream.Close();
            return retString;
        }

        /// <summary>
        /// Post方法（带参数
        /// </summary>
        /// <param name="url">地址</param>
        /// <param name="postString">post数据的字符串</param>
        /// <param name="timeout">超时时间，默认为60000毫秒（1分钟）</param>
        /// <returns></returns>
        public static string PostHttpResponse(string url, IDictionary<string, string> parameters, int timeout = 60000)
        {
            HttpWebRequest request = null;
            //HTTPSQ请求
            request = WebRequest.Create(url) as HttpWebRequest;
            request.ProtocolVersion = HttpVersion.Version10;
            request.Method = "POST";
            request.ContentType = "application/x-www-form-urlencoded";
            request.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)";
            request.Timeout = timeout;

            //往头部加入自定义验证信息

            SetHeaderValue(request.Headers, "Authorization", jwttoken);

            //如果需要POST数据
            if (!(parameters == null || parameters.Count == 0))
            {
                StringBuilder buffer = new StringBuilder();
                int i = 0;
                foreach (string key in parameters.Keys)
                {
                    if (i > 0)
                    {
                        buffer.AppendFormat("&{0}={1}", key, parameters[key]);
                    }
                    else
                    {
                        buffer.AppendFormat("{0}={1}", key, parameters[key]);
                    }
                    i++;
                }
                byte[] data = Encoding.GetEncoding("utf-8").GetBytes(buffer.ToString());
                using (Stream stream = request.GetRequestStream())
                {
                    stream.Write(data, 0, data.Length);
                }
            }
            var resultStream = (request.GetResponse() as HttpWebResponse);
            string result = "";
            //获取响应内容
            using (StreamReader reader = new StreamReader(resultStream.GetResponseStream(), Encoding.UTF8))
            {
                result = reader.ReadToEnd();
            }
            return result;
        }
        /// <summary>
        /// Post方法（登录获取token）
        /// </summary>
        /// <param name="url">地址</param>
        /// <param name="postString">post数据的字符串</param>
        /// <param name="timeout">超时时间，默认为60000毫秒（1分钟）</param>
        /// <returns></returns>
        public static string LoginHttpResponse(string url, Object postData, int timeout = 60000)
        {
            HttpWebRequest request = null;
            //HTTPSQ请求
            request = WebRequest.Create(url) as HttpWebRequest;
            request.ProtocolVersion = HttpVersion.Version10;
            request.Method = "POST";
            request.ContentType = "application/json";
            request.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)";
            request.Timeout = timeout;

            //如果需要POST数据
            string str = JsonConvert.SerializeObject(postData);
            byte[] data = Encoding.GetEncoding("utf-8").GetBytes(str);
            using (Stream stream = request.GetRequestStream())
            {
                stream.Write(data, 0, data.Length);
            }

            var resultStream = (request.GetResponse() as HttpWebResponse);
            string result = "";
            //获取响应内容
            using (StreamReader reader = new StreamReader(resultStream.GetResponseStream(), Encoding.UTF8))
            {
                result = reader.ReadToEnd();
            }
            return result;
        }

        /// <summary>
        /// post方法（使用该方法请求Api时，Api中参数前需要加[FromBody]）
        /// </summary>
        /// <param name="url">地址</param>
        /// <param name="PostData">post数据对象</param>
        /// <param name="timeout">超时时间，默认为60000毫秒（1分钟）</param>
        /// <returns></returns>
        public static string PostHttpResponse(string url, Object postData, int timeout = 60000)
        {
            HttpWebRequest request = null;
            //HTTPSQ请求
            request = WebRequest.Create(url) as HttpWebRequest;
            request.ProtocolVersion = HttpVersion.Version10;
            request.Method = "POST";
            request.ContentType = "application/json";
            request.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727)";
            request.Timeout = timeout;

            //往头部加入自定义验证信息

            SetHeaderValue(request.Headers, "Authorization", jwttoken);

            //如果需要POST数据
            string str = JsonConvert.SerializeObject(postData);
            byte[] data = Encoding.GetEncoding("utf-8").GetBytes(str);
            using (Stream stream = request.GetRequestStream())
            {
                stream.Write(data, 0, data.Length);
            }

            var resultStream = (request.GetResponse() as HttpWebResponse);
            string result = "";
            //获取响应内容
            using (StreamReader reader = new StreamReader(resultStream.GetResponseStream(), Encoding.UTF8))
            {
                result = reader.ReadToEnd();
            }
            return result;
        }

        /// <summary>
        /// 往头部加信息
        /// </summary>
        /// <param name="header"></param>
        /// <param name="name"></param>
        /// <param name="value"></param>
        public static void SetHeaderValue(WebHeaderCollection header, string name, string value)
        {
            var property = typeof(WebHeaderCollection).GetProperty("InnerCollection", BindingFlags.Instance | BindingFlags.NonPublic);
            if (property != null)
            {
                var collection = property.GetValue(header, null) as NameValueCollection;
                collection[name] = value;
            }
        }
    }