using System;

 using System.IO;

 using System.Net;

 using System.Text;

 using System.Web.Script.Serialization;

 namespace IpUtils

 {

     public class IpDetail

     {

         public String Ret { get; set; }

         public String Start { get; set; }

         public String End { get; set; }

         public String Country { get; set; }

         public String Province { get; set; }

         public String City { get; set; }

         public String District { get; set; }

         public String Isp { get; set; }

         public String Type { get; set; }

         public String Desc { get; set; }

     }

     public class IpHelper

     {

         /// <summary>

         /// 获取IP地址的详细信息，调用的借口为

         /// http://int.dpool.sina.com.cn/iplookup/iplookup.php?format=json&ip={ip}

         /// </summary>

         /// <param name="ipAddress">请求分析得IP地址</param>

         /// <param name="sourceEncoding">服务器返回的编码类型</param>

         /// <returns>IpUtils.IpDetail</returns>

         public static IpDetail Get(String ipAddress,Encoding sourceEncoding)

         {

             String ip = string.Empty;

             if(sourceEncoding==null)

                 sourceEncoding = Encoding.UTF8;

             using (var receiveStream = WebRequest.Create("http://int.dpool.sina.com.cn/iplookup/iplookup.php?format=json&ip="+ipAddress).GetResponse().GetResponseStream())

             {

                 using (var sr = new StreamReader(receiveStream, sourceEncoding))

                 {

                     var readbuffer = new char[];

                     int n = sr.Read(readbuffer, , readbuffer.Length);

                     int realLen = ;

                     while (n > )

                     {

                         realLen = n;

                         n = sr.Read(readbuffer, , readbuffer.Length);

                     }

                     ip = sourceEncoding.GetString(sourceEncoding.GetBytes(readbuffer, , realLen));

                 }

             }

             return  !string.IsNullOrEmpty(ip)?new JavaScriptSerializer().Deserialize<IpDetail>(ip):null;

         }

     }

     public class EncodingHelper

     {

         public static String GetString(Encoding source, Encoding dest, String soureStr)

         {

             return dest.GetString(Encoding.Convert(source, dest, source.GetBytes(soureStr)));

         }

         public static String GetString(Encoding source, Encoding dest, Char[] soureCharArr, int offset, int len)

         {

             return dest.GetString(Encoding.Convert(source, dest, source.GetBytes(soureCharArr, offset, len)));

         }

     }

 }