如何自动判断url中汉字的编码格式

参考了http://topic.csdn.net/u/20091105/15/0d54b7b2-38fe-4cdf-ae1b-5a1f07c26ea0.html帖子18楼的代码

 

修改了一下，满足了我实际的项目需求

using  System;
using  System.Collections.Generic;
using  System.Linq;
using  System.Text;
using  System.Web;

namespace  testProgram
{
     class  MyEncoding
    {

         static   void  Main()
        {
            MyEncoding myEncoding  =   new  MyEncoding();
             // GB2312
             string  gb2312  =   " http://www.baidu.com/s?wd=%B9%A4%B3%A7%B9%A9%B5%E7 " ;
             // utf8
             string  utf8  =   " http://www.google.com.hk/search?hl=zh-CN&newwindow=1&safe=strict&q=%25abc%E4%B8%AD%E5%9B%BD%2C%3B&btnG=Google+%E6%90%9C%E7%B4%A2&aq=f&aqi=&aql=&oq=&gs_rfai= " ;

             string  ss  =  myEncoding.UrlDecode(gb2312);
             string  ss1  =  myEncoding.UrlDecode(utf8);

            Console.WriteLine(ss);
            Console.WriteLine(ss1);

            Console.ReadLine();
        }

         private   string  UrlDecode( string  url)
        {
             string  result  =   "" ;
             byte [] buf  =  GetUrlCodingToBytes(url);
             if  (IsUTF8(buf))
            {
                result  =  HttpUtility.UrlDecode(url, Encoding.UTF8);
            }
             else
            {
                result  =  HttpUtility.UrlDecode(url, Encoding.GetEncoding( " GB2312 " ));
            }
             return  result;
        }

         private   byte [] GetUrlCodingToBytes( string  url)
        {
            StringBuilder sb  =   new  StringBuilder();

             int  i  =  url.IndexOf( ' % ' );
             while  (i  >=   0 )
            {
                 if  (url.Length  <  i  +   3 )
                {
                     break ;
                }
                sb.Append(url.Substring(i,  3 ));
                url  =  url.Substring(i  +   3 );
                i  =  url.IndexOf( ' % ' );
            }

             string  urlCoding  =  sb.ToString();
             if  ( string .IsNullOrEmpty(urlCoding))
                 return   new   byte [ 0 ];

            urlCoding  =  urlCoding.Replace( " % " ,  string .Empty);
             int  len  =  urlCoding.Length  /   2 ;
             byte [] result  =   new   byte [len];
            len  *=   2 ;
             for  ( int  index  =   0 ; index  <  len; index ++ )
            {
                 string  s  =  urlCoding.Substring(index,  2 );
                 int  b  =   int .Parse(s, System.Globalization.NumberStyles.HexNumber);
                result[index  /   2 ]  =  ( byte )b;
                index ++ ;
            }
             return  result;
        }

         private   bool  IsUTF8( byte [] buf)
        {
             int  i;
             byte  cOctets;  //  octets to go in this UTF-8 encoded character  
             bool  bAllAscii  =   true ;
             long  iLen  =  buf.Length;
            cOctets  =   0 ;
             for  (i  =   0 ; i  <  iLen; i ++ )
            {
                 if  ((buf[i]  &   0x80 )  !=   0 ) bAllAscii  =   false ;

                 if  (cOctets  ==   0 )
                {
                     if  (buf[i]  >=   0x80 )
                    {
                         do
                        {
                            buf[i]  <<=   1 ;
                            cOctets ++ ;
                        }
                         while  ((buf[i]  &   0x80 )  !=   0 );

                        cOctets -- ;
                         if  (cOctets  ==   0 )
                             return   false ;
                    }
                }
                 else
                {
                     if  ((buf[i]  &   0xC0 )  !=   0x80 )
                         return   false ;
                    cOctets -- ;
                }
            }
             if  (cOctets  >   0 )
                 return   false ;
             if  (bAllAscii)
                 return   false ;
             return   true ;
        }
    }
}