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asp.net下载文件方法

/*
* 输入参数
* _Request: Page.Request 对象
* _Response: Page.Response 对象
* _fileName: 下载文件名
* _fullPath: 带文件名下载路径
* _speed 每秒允许下载的字节数
* 返回是否成功

*/

public static bool ResponseFile(HttpRequest _Request,HttpResponse _Response,string _fileName,string _fullPath, long _speed) { 
       try { 
           FileStream myFile = new FileStream(_fullPath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite); 
           BinaryReader br = new BinaryReader(myFile); 
           try { 
               _Response.AddHeader("Accept-Ranges", "bytes"); 
               _Response.Buffer = false; 
               long fileLength = myFile.Length; 
               long startBytes = 0; 

               int pack = 10240; //10K bytes     
               //int sleep = 200; //每秒5次 即5*10K bytes每秒     
               int sleep = (int)Math.Floor(1000 * pack / _speed) + 1; 
               if (_Request.Headers["Range"] != null) { 
                   _Response.StatusCode = 206; 
                   string[] range = _Request.Headers["Range"].Split(new char[] {@#=@#, @#-@#}); 
                   startBytes = Convert.ToInt64(range[1]); 
               } 
               _Response.AddHeader("Content-Length", (fileLength - startBytes).ToString()); 
               if (startBytes != 0) { 
                   _Response.AddHeader("Content-Range", string.Format(" bytes {0}-{1}/{2}", startBytes, fileLength-1, fileLength)); 
               } 
               _Response.AddHeader("Connection", "Keep-Alive"); 
               _Response.ContentType = "application/octet-stream"; 
               _Response.AddHeader("Content-Disposition","attachment;filename=" + HttpUtility.UrlEncode(_fileName,System.Text.Encoding.UTF8) ); 

               br.BaseStream.Seek(startBytes, SeekOrigin.Begin); 
               int maxCount = (int) Math.Floor((fileLength - startBytes) / pack) + 1; 

               for (int i = 0;i < maxCount;i++) { 
                   if (_Response.IsClientConnected) {     
                       _Response.BinaryWrite(br.ReadBytes(pack)); 
                       Thread.Sleep(sleep); 
                   }else {     
                       i=maxCount; 
                   } 
               } 
           }catch {     
               return false; 
           }finally {     
               br.Close(); 
               myFile.Close(); 
           } 
       }catch {     
           return false; 
       } 
       return true; 
}
 

调用例

Page.Response.Clear(); 

bool success = ResponseFile(Page.Request, Page.Response, "filename", @"C:\download.date", 1024000); 

if(!success)     
       Response.Write("下载文件出错!"); 

Page.Response.End();
 
如何通过ASP.NET来下载文件,这个问题我们经常遇到,把常用的方法总结到一起,学习学习。当我们要让用户下载一个文件,最简单的方式是通过Response.Redirect指令: 

Response.Redirect("test.doc")


您可以把上面这行指令放在Button的Click事件当中,当用户点击按钮之后,网页就会被转址到该word档,造成下载的效果。

但是这样的下载有几个问题:

1、无法下载不存在的文件:例如,我们若是想把程序动态(临时)产生的文字,当作一个文件下载的时候(也就是该文件其实原先并不是真的存在,而是动态产生的),就无法下载。

2、无法下载存储于数据库中的文件:这是类似的问题,该文件并没有真的存在,只是被存放在数据库中的某个位置(某笔记录中的某个栏位)的时候,就无法下载。

3、无法下载不存在于Web文件夹中的文件:文件确实存在,但该文件夹并不是可以分享出来的Web文件夹,例如,该文件的位置在C:\winnt,您总不会想要把该文件夹当作Web文件夹吧?这时候,由于您无法使用Redirect指向该位置,所以无法下载。

4、下载文件后,原本的页面将会消失。

典型的状况是,我们要让用户下载一个.txt文件或是.csv格式的Excel文件,但是...

1、这个文件可能是通过ASP.NET程序动态产生的,而不是确实存在于Server端的文件;

2、或是它虽然存在于伺服器端的某个实体位置,但我们并不想暴露这个位置(如果这个位置公开,很可能没有权限的用户也可以在网址栏上输入URL直接取得!!!)

3、或是这个位置并不在网站虚拟路径所在的文件夹中。(例如C:\Windows\System32...)


   //TransmitFile实现下载

    protected void Button1_Click(object sender, EventArgs e)

    {

        /*

        微软为Response对象提供了一个新的方法TransmitFile来解决使用Response.BinaryWrite

        下载超过400mb的文件时导致Aspnet_wp.exe进程回收而无法成功下载的问题。

        代码如下:

        */

        Response.ContentType = "application/x-zip-compressed";

        Response.AddHeader("Content-Disposition", "attachment;filename=z.zip");

        string filename = Server.MapPath("DownLoad/z.zip");

        Response.TransmitFile(filename);

    }

    //WriteFile实现下载

    protected void Button2_Click(object sender, EventArgs e)

    {

        /*

        using System.IO;

        */

        string fileName = "asd.txt";//客户端保存的文件名

        string filePath = Server.MapPath("DownLoad/aaa.txt");//路径

        FileInfo fileInfo = new FileInfo(filePath);

        Response.Clear();

        Response.ClearContent();

        Response.ClearHeaders();

        Response.AddHeader("Content-Disposition", "attachment;filename=" + fileName);

        Response.AddHeader("Content-Length", fileInfo.Length.ToString());

        Response.AddHeader("Content-Transfer-Encoding", "binary");

        Response.ContentType = "application/octet-stream";

        Response.ContentEncoding = System.Text.Encoding.GetEncoding("gb2312");

        Response.WriteFile(fileInfo.FullName);

        Response.Flush();

        Response.End();

    }

    //WriteFile分块下载

    protected void Button3_Click(object sender, EventArgs e)

    {

        string fileName = "aaa.txt";//客户端保存的文件名

        string filePath = Server.MapPath("DownLoad/aaa.txt");//路径

        System.IO.FileInfo fileInfo = new System.IO.FileInfo(filePath);

        if (fileInfo.Exists == true)

        {

            const long ChunkSize = 102400;//100K 每次读取文件,只读取100K,这样可以缓解服务器的压力

            byte[] buffer = new byte[ChunkSize];

            Response.Clear();

            System.IO.FileStream iStream = System.IO.File.OpenRead(filePath);

            long dataLengthToRead = iStream.Length;//获取下载的文件总大小

            Response.ContentType = "application/octet-stream";

            Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(fileName));

            while (dataLengthToRead > 0 && Response.IsClientConnected)

            {

                int lengthRead = iStream.Read(buffer, 0, Convert.ToInt32(ChunkSize));//读取的大小

                Response.OutputStream.Write(buffer, 0, lengthRead);

                Response.Flush();

                dataLengthToRead = dataLengthToRead - lengthRead;

            }

            Response.Close();

        }

    }

    //流方式下载

    protected void Button4_Click(object sender, EventArgs e)

    {

        string fileName = "aaa.txt";//客户端保存的文件名

        string filePath = Server.MapPath("DownLoad/aaa.txt");//路径

        //以字符流的形式下载文件

        FileStream fs = new FileStream(filePath, FileMode.Open);

        byte[] bytes = new byte[(int)fs.Length];

        fs.Read(bytes, 0, bytes.Length);

        fs.Close();

        Response.ContentType = "application/octet-stream";

        //通知浏览器下载文件而不是打开

        Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8));

        Response.BinaryWrite(bytes);

        Response.Flush();

        Response.End();

    }

//----------------------------------------------------------


public void DownloadFile( System.Web.UI.Page WebForm,String FileNameWhenUserDownload ,String FileBody )

{

  WebForm.Response.ClearHeaders();

  WebForm.Response.Clear();

  WebForm.Response.Expires = 0;

  WebForm.Response.Buffer = true;

  WebForm.Response.AddHeader("Accept-Language", "zh-tw");

  //'文件名称

  WebForm.Response.AddHeader("content-disposition", "attachment; filename='"+System.Web.HttpUtility.UrlEncode(FileNameWhenUserDownload, System.Text.Encoding.UTF8)+"'");

  WebForm.Response.ContentType = "Application/octet-stream";

  //'文件内容

  WebForm.Response.Write(FileBody);//-----------

    WebForm.Response.End();

}

//上面这段代码是下载一个动态产生的文本文件,若这个文件已经存在于服务器端的实体路径,则可以通过下面的函数:

public void DownloadFileByFilePath( System.Web.UI.Page WebForm,String FileNameWhenUserDownload ,String FilePath )

{

  WebForm.Response.ClearHeaders();

  WebForm.Response.Clear();

  WebForm.Response.Expires = 0;

    WebForm.Response.Buffer = true;

  WebForm.Response.AddHeader("Accept-Language", "zh-tw");

  //文件名称

  WebForm.Response.AddHeader("content-disposition", "attachment; filename='" + System.Web.HttpUtility.UrlEncode(FileNameWhenUserDownload, System.Text.Encoding.UTF8) +"'" );

  WebForm.Response.ContentType = "Application/octet-stream";

  //文件内容

  WebForm.Response.Write(System.IO.File.ReadAllBytes(FilePath));//---------

  WebForm.Response.End();

}

 

 

 

下面是更详细的ContentType
'ez' => 'application/andrew-inset',
'hqx' => 'application/mac-binhex40',
'cpt' => 'application/mac-compactpro',
'doc' => 'application/msword',
'bin' => 'application/octet-stream',
'dms' => 'application/octet-stream',
'lha' => 'application/octet-stream',
'lzh' => 'application/octet-stream',
'exe' => 'application/octet-stream',
'class' => 'application/octet-stream',
'so' => 'application/octet-stream',
'dll' => 'application/octet-stream',
'oda' => 'application/oda',
'pdf' => 'application/pdf',
'ai' => 'application/postscript',
'eps' => 'application/postscript',
'ps' => 'application/postscript',
'smi' => 'application/smil',
'smil' => 'application/smil',
'mif' => 'application/vnd.mif',
'xls' => 'application/vnd.ms-excel',
'ppt' => 'application/vnd.ms-powerpoint',
'wbxml' => 'application/vnd.wap.wbxml',
'wmlc' => 'application/vnd.wap.wmlc',
'wmlsc' => 'application/vnd.wap.wmlscriptc',
'bcpio' => 'application/x-bcpio',
'vcd' => 'application/x-cdlink',
'pgn' => 'application/x-chess-pgn',
'cpio' => 'application/x-cpio',
'csh' => 'application/x-csh',
'dcr' => 'application/x-director',
'dir' => 'application/x-director',
'dxr' => 'application/x-director',
'dvi' => 'application/x-dvi',
'spl' => 'application/x-futuresplash',
'gtar' => 'application/x-gtar',
'hdf' => 'application/x-hdf',
'js' => 'application/x-javascript',
'skp' => 'application/x-koan',
'skd' => 'application/x-koan',
'skt' => 'application/x-koan',
'skm' => 'application/x-koan',
'latex' => 'application/x-latex',
'nc' => 'application/x-netcdf',
'cdf' => 'application/x-netcdf',
'sh' => 'application/x-sh',
'shar' => 'application/x-shar',
'swf' => 'application/x-shockwave-flash',
'sit' => 'application/x-stuffit',
'sv4cpio' => 'application/x-sv4cpio',
'sv4crc' => 'application/x-sv4crc',
'tar' => 'application/x-tar',
'tcl' => 'application/x-tcl',
'tex' => 'application/x-tex',
'texinfo' => 'application/x-texinfo',
'texi' => 'application/x-texinfo',
't' => 'application/x-troff',
'tr' => 'application/x-troff',
'roff' => 'application/x-troff',
'man' => 'application/x-troff-man',
'me' => 'application/x-troff-me',
'ms' => 'application/x-troff-ms',
'ustar' => 'application/x-ustar',
'src' => 'application/x-wais-source',
'xhtml' => 'application/xhtml+xml',
'xht' => 'application/xhtml+xml',
'zip' => 'application/zip',
'au' => 'audio/basic',
'snd' => 'audio/basic',
'mid' => 'audio/midi',
'midi' => 'audio/midi',
'kar' => 'audio/midi',
'mpga' => 'audio/mpeg',
'mp2' => 'audio/mpeg',
'mp3' => 'audio/mpeg',
'aif' => 'audio/x-aiff',
'aiff' => 'audio/x-aiff',
'aifc' => 'audio/x-aiff',
'm3u' => 'audio/x-mpegurl',
'ram' => 'audio/x-pn-realaudio',
'rm' => 'audio/x-pn-realaudio',
'rpm' => 'audio/x-pn-realaudio-plugin',
'ra' => 'audio/x-realaudio',
'wav' => 'audio/x-wav',
'pdb' => 'chemical/x-pdb',
'xyz' => 'chemical/x-xyz',
'bmp' => 'image/bmp',
'gif' => 'image/gif',
'ief' => 'image/ief',
'jpeg' => 'image/jpeg',
'jpg' => 'image/jpeg',
'jpe' => 'image/jpeg',
'png' => 'image/png',
'tiff' => 'image/tiff',
'tif' => 'image/tiff',
'djvu' => 'image/vnd.djvu',
'djv' => 'image/vnd.djvu',
'wbmp' => 'image/vnd.wap.wbmp',
'ras' => 'image/x-cmu-raster',
'pnm' => 'image/x-portable-anymap',
'pbm' => 'image/x-portable-bitmap',
'pgm' => 'image/x-portable-graymap',
'ppm' => 'image/x-portable-pixmap',
'rgb' => 'image/x-rgb',
'xbm' => 'image/x-xbitmap',
'xpm' => 'image/x-xpixmap',
'xwd' => 'image/x-xwindowdump',
'igs' => 'model/iges',
'iges' => 'model/iges',
'msh' => 'model/mesh',
'mesh' => 'model/mesh',
'silo' => 'model/mesh',
'wrl' => 'model/vrml',
'vrml' => 'model/vrml',
'css' => 'text/css',
'html' => 'text/html',
'htm' => 'text/html',
'asc' => 'text/plain',
'txt' => 'text/plain',
'rtx' => 'text/richtext',
'rtf' => 'text/rtf',
'sgml' => 'text/sgml',
'sgm' => 'text/sgml',
'tsv' => 'text/tab-separated-values',
'wml' => 'text/vnd.wap.wml',
'wmls' => 'text/vnd.wap.wmlscript',
'etx' => 'text/x-setext',
'xsl' => 'text/xml',
'xml' => 'text/xml',
'mpeg' => 'video/mpeg',
'mpg' => 'video/mpeg',
'mpe' => 'video/mpeg',
'qt' => 'video/quicktime',
'mov' => 'video/quicktime',
'mxu' => 'video/vnd.mpegurl',
'avi' => 'video/x-msvideo',
'movie' => 'video/x-sgi-movie',
'ice' => 'x-conference/x-cooltalk'

 

 

 

转载: http://www.cnblogs.com/kingkoo/archive/2009/08/08/1541593.html

posted on 2010-02-23 14:34  rabow  阅读(4410)  评论(0编辑  收藏  举报