服务器多个文件打包压缩下载

using  System;
using  System.Data;
using  System.Configuration;
using  System.Collections;
using  System.Web;
using  System.Web.Security;
using  System.Web.UI;
using  System.Web.UI.WebControls;
using  System.Web.UI.WebControls.WebParts;
using  System.Web.UI.HtmlControls;
using  zhan.File;
using  ICSharpCode.SharpZipLib.Zip;
using  System.IO;
using  ICSharpCode.SharpZipLib.Checksums;

public   partial   class  downfile : System.Web.UI.Page
{
     protected   void  Page_Load( object  sender, EventArgs e)
    {
         if  (Request.QueryString[ " path " ]  !=   null   &&  Request.QueryString[ " path " ].ToString()  !=   "" )
        {
            package(Request.QueryString[ " path " ].ToString());
        }
        
    }
     private   void  package( string  filename)
    {
         string  file  =  filename.Substring( 0 , filename.LastIndexOf( ' . ' ));
         string  suffix  =  filename.Substring(filename.LastIndexOf( ' . ' ), filename.Length  -  filename.LastIndexOf( ' . ' ));
        
         string [] files  = { filename, file  +   " _2 "   +  suffix, file  +   " _3 "   +  suffix };
        
         string  zipname  =  DateTime.Now.ToString( " yyyyMMddHHmmss " )  +   " .zip " ;
         string  zippath  =   " ~/upload/temp/ "   +  zipname;
        ZipFileDictory(files, zippath);

        FileStream fs  =  File.OpenRead(Server.MapPath(zippath));
         byte [] buffer  =   new   byte [ 102400 ];
         long  dataLengthToRead  =  fs.Length; // 获取下载的文件总大小 

        fs.Position  =   0 ;
        Response.ContentType  =   " application/octet-stream " ;
        Response.AddHeader( " Content-Length " , fs.Length.ToString());
        Response.AddHeader( " content-disposition " ,  " attachment;filename= "   + HttpUtility.UrlEncode(zipname));
         while  (dataLengthToRead  >   0   &&  Response.IsClientConnected)
        {
             int  lengthRead  =  fs.Read(buffer,  0 , buffer.Length); // 读取的大小 
            Response.OutputStream.Write(buffer,  0 , lengthRead);
            Response.Flush();
            dataLengthToRead  =  dataLengthToRead  -  lengthRead;
        }
        fs.Close();
        fs.Dispose();
        File.Delete(Server.MapPath(zippath));
        Response.End();
    }
     public   void  ZipFileDictory( string [] filenames,  string  filename)
    {
        Crc32 crc  =   new  Crc32();
        ZipOutputStream s  =   new  ZipOutputStream(System.IO.File.Create(System.Web.HttpContext.Current.Server.MapPath(filename)));
        s.SetLevel( 6 );

         foreach  ( string  file  in  filenames)
        {
             if  (File.Exists(System.Web.HttpContext.Current.Server.MapPath(file)))
            {
                FileStream fs  =  System.IO.File.OpenRead(System.Web.HttpContext.Current.Server.MapPath(file));

                 byte [] buffer  =   new   byte [fs.Length];
                fs.Read(buffer,  0 , buffer.Length);
                ZipEntry entry  =   new  ZipEntry(file.Substring(file.LastIndexOf( ' / ' )  +   1 , file.Length  -  file.LastIndexOf( ' / ' )  -   1 ));

                entry.DateTime  =  DateTime.Now;

                entry.Size  =  fs.Length;
                fs.Close();

                crc.Reset();
                crc.Update(buffer);

                entry.Crc  =  crc.Value;

                s.PutNextEntry(entry);

                s.Write(buffer,  0 , buffer.Length);
            }
        }

        s.Finish();
        s.Close();
    }
}