public string ReadUrlContent(string rUrl)
    {

        // used to build entire input
        StringBuilder sb = new StringBuilder();
        // 请求该页面
        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(rUrl);
        // 获取返回的数据（通过相应）
        HttpWebResponse response = (HttpWebResponse)request.GetResponse();
        //将读取到的数据放入到流里面
        Encoding enc = Encoding.GetEncoding("GB2312");
        //如果是乱码就改成 utf-8 / GB2312
        StreamReader loResponseStream = new StreamReader(response.GetResponseStream(), enc);
        sb.Append(loResponseStream.ReadToEnd());
        loResponseStream.Close();
        return sb.ToString();
    }