GET方式的HTTP请求,返回响应体

        public static readonly string DefaultUserAgent = "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.2; .NET CLR 1.1.4322; .NET CLR 2.0.50727)";

        /// <summary>
        /// GET方式的HTTP请求
        /// </summary>
        /// <param name="targetUri"></param>
        /// <param name="timeout">超时时间</param>
        /// <param name="cookie">随同HTTP请求发送的Cookie信息</param>
        /// <returns></returns>
        public static HttpWebRequest CreateGetHttpWebRequest(string targetUri, int timeout = 0, CookieCollection cookie = null)
        {
            HttpWebRequest request = WebRequest.Create(targetUri) as HttpWebRequest;
            request.UserAgent = DefaultUserAgent;
            request.Method = "GET";

            if (timeout != 0)
                request.Timeout = timeout;
            if (cookie != null)
            {
                request.CookieContainer = new CookieContainer();
                request.CookieContainer.Add(cookie);
            }

            return request;
        }

        /// <summary>
        /// 读取http响应信息，并返回响应体
        /// </summary>
        /// <param name="response">HttpWebResponse对象</param>
        /// <returns></returns>
        public static string ReaderFromHttp(HttpWebResponse response)
        {
            Stream stream = null;
            StreamReader streamReader = null;
            try
            {
                var contentEncoding = response.ContentEncoding;
                stream = response.GetResponseStream();
                if (contentEncoding == "gzip")
                {
                    /*压缩数据，要进行处理*/
                    throw new NotImplementedException("gzip压缩数据处理还么实现");
                }
                else
                {
                    streamReader = new StreamReader(stream, Encoding.UTF8);
                    return streamReader.ReadToEnd();
                }

            }
            catch (Exception e)
            {
                return null;
            }
            finally
            {
                if (streamReader != null)
                {
                    streamReader.Close();
                    streamReader = null;
                }
                if (stream != null)
                {
                    stream.Close();
                    stream = null;
                }
            }
        }

        /// <summary>
        /// GET方式的HTTP请求,返回响应体
        /// </summary>
        /// <param name="targetUri"></param>
        /// <param name="timeout">超时时间</param>
        /// <param name="cookie">随同HTTP请求发送的Cookie信息</param>
        /// <returns></returns>
        public static string ReturnFromGetHttp(string targetUri, int timeout = 0, CookieCollection cookie = null)
        {
            HttpWebRequest request = null;
            HttpWebResponse response = null;
            try
            {
                request = CreateGetHttpWebRequest(targetUri, timeout, cookie);
                response = request.GetResponse() as HttpWebResponse;

                return ReaderFromHttp(response);
            }
            catch (Exception e)
            {
                return null;
            }
            finally
            {
                if (response != null)
                {
                    response.Close();
                    response = null;
                }
                if (request != null)
                {
                    request.Abort();
                    request = null;
                }
            }
        }