public string Get_Http(string a_strUrl,int timeout)
        {
            string strResult ;         
 
            try
            {
HttpWebRequest myReq = (HttpWebRequest)HttpWebRequest.Create(a_strUrl) ;
                myReq.Timeout = timeout;
                HttpWebResponse HttpWResp = (HttpWebResponse)myReq.GetResponse();
            
                Stream myStream = HttpWResp.GetResponseStream () ;
 
                StreamReader sr = new StreamReader(myStream , Encoding.Default);
                StringBuilder strBuilder = new StringBuilder();
                while (-1 != sr.Peek())
                {
                    strBuilder.Append(sr.ReadLine()+"\r\n");
                }
 
                strResult = strBuilder.ToString();
            }
            catch(Exception exp)
            {
                strResult = "错误：" + exp.Message ;
            }
 
            return strResult ;
 
        }