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GET /image/index_r4_c1.jpg HTTP/1.1

Accept: */*

Referer: http://192.168.3.120:8080

Accept-Language: zh-cn

Accept-Encoding: gzip, deflate

User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0; .NET CLR 1.0.3705)

Host: 192.168.3.120:8080

Connection: Keep-Alive

HTTP/1.1 200 OK

Server: Microsoft-IIS/5.0

Date: Tue, 24 Jun 2003 05:39:40 GMT

Content-Type: image/jpeg

Accept-Ranges: bytes

Last-Modified: Thu, 23 May 2002 03:05:40 GMT

ETag: "bec48eb862c21:934"

Content-Length: 2827

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Accept: */*

Referer: http://192.168.3.120:8080

Accept-Language: zh-cn

Accept-Encoding: gzip, deflate

User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.0; .NET CLR 1.0.3705)

Host: 192.168.3.120:8080

Range:bytes=1024-

Connection: Keep-Alive

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System.Net.HttpWebRequest

HttpWebRequest Àà¶Ô WebRequest Öж¨ÒåµÄÊôÐԺͷ½·¨Ìṩ֧³Ö£¬Ò²¶ÔʹÓû§Äܹ»Ö±½ÓÓëʹÓà HTTP µÄ·þÎñÆ÷½»»¥µÄ¸½¼ÓÊôÐԺͷ½·¨Ìṩ֧³Ö¡£

HttpWebRequest ½«·¢Ë͵½ Internet ×ÊÔ´µÄ¹«¹² HTTP ±êÍ·Öµ¹«¿ªÎªÊôÐÔ£¬ÓÉ·½·¨»òϵͳÉèÖá£Ï±í°üº¬ÍêÕûÁÐ±í¡£¿ÉÒÔ½« Headers ÊôÐÔÖеÄÆäËû±êÍ·ÉèÖÃΪÃû³Æ/Öµ¶Ô¡£µ«ÊÇ×¢Ò⣬ijЩ¹«¹²±êÍ·±»ÊÓΪÊÜÏÞÖƵģ¬ËüÃÇ»òÕßÖ±½ÓÓÉ API¹«¿ª£¬»òÕßÊܵ½ÏµÍ³±£»¤£¬²»Äܱ»¸ü¸Ä¡£RangeÒ²ÊôÓÚ±»±£»¤Ö®ÁУ¬²»¹ý£¬.NETΪ¿ª·¢ÕßÌṩÁ˸ü·½±ãµÄ²Ù×÷£¬¾ÍÊÇ AddRange·½·¨£¬ÏòÇëÇóÌí¼Ó´ÓÇëÇóÊý¾ÝµÄ¿ªÊ¼´¦»ò½áÊø´¦µÄÌض¨·¶Î§µÄ×Ö½Ú·¶Î§±êÍ·

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System.IO.FileStream

FileStream ¶ÔÏóÖ§³ÖʹÓÃSeek·½·¨¶ÔÎļþ½øÐÐËæ»ú·ÃÎÊ, Seek ÔÊÐí½«¶ÁÈ¡/дÈëλÖÃÒƶ¯µ½ÎļþÖеÄÈÎÒâλÖá£ÕâÊÇͨ¹ý×Ö½ÚÆ«ÒƲο¼µã²ÎÊýÍê³ÉµÄ¡£×Ö½ÚÆ«ÒÆÁ¿ÊÇÏà¶ÔÓÚ²éÕҲο¼µã¶øÑԵģ¬¸Ã²Î¿¼µã¿ÉÒÔÊÇ»ù´¡ÎļþµÄ¿ªÊ¼¡¢µ±Ç°Î»Öûò½á⣬·Ö±ðÓÉSeekOriginÀàµÄÈý¸öÊôÐÔ±íʾ¡£

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static void Main(string[] args)

              {

                     string StrFileName="c:\\aa.zip";      //¸ù¾Ýʵ¼ÊÇé¿öÉèÖÃ

                     string StrUrl="http://www.xxxx.cn/xxxxx.zip";   //¸ù¾Ýʵ¼ÊÇé¿öÉèÖÃ

                     //´ò¿ªÉÏ´ÎÏÂÔصÄÎļþ»òн¨Îļþ

                     long lStartPos =0;

                     System.IO.FileStream fs;

                     if (System.IO.File.Exists(StrFileName))

                     {

                            fs= System.IO.File.OpenWrite(StrFileName);

                            lStartPos=fs.Length;

                            fs.Seek(lStartPos,System.IO.SeekOrigin.Current);   //Òƶ¯ÎļþÁ÷Öеĵ±Ç°Ö¸Õë

                     }

                     else

                     {

                            fs = new System.IO.FileStream(StrFileName,System.IO.FileMode.Create);

                            lStartPos =0;

                     }

                     //´ò¿ªÍøÂçÁ¬½Ó

                     try

                     {

                            System.Net.HttpWebRequest request =(System.Net.HttpWebRequest)System.Net.HttpWebRequest.Create(StrUrl);

                            if ( lStartPos>0)

                                   request.AddRange((int)lStartPos);    //ÉèÖÃRangeÖµ

                            //Ïò·þÎñÆ÷ÇëÇ󣬻ñµÃ·þÎñÆ÷»ØÓ¦Êý¾ÝÁ÷

                            System.IO.Stream ns= request.GetResponse().GetResponseStream();

                            byte[] nbytes = new byte[512];

                            int nReadSize=0;

                            nReadSize=ns.Read(nbytes,0,512);

                            while( nReadSize >0)

                            {

                                   fs.Write(nbytes,0,nReadSize);

                                   nReadSize=ns.Read(nbytes,0,512);

                            }

                            fs.Close();

                            ns.Close();

                            Console.WriteLine("ÏÂÔØÍê³É");

                     }

                     catch(Exception ex)

                     {

                            fs.Close();

                            Console.WriteLine("ÏÂÔعý³ÌÖгöÏÖ´íÎó:"+ex.ToString());

                     }

              }

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