Example file download servlet

frost137 (Douglas Wyatt) — Tue, 09 Oct 2007 23:12:04 GMT
// description of your code here


  /**

     *  Sends a file to the ServletResponse output stream.  Typically

     *  you want the browser to receive a different name than the

     *  name the file has been saved in your local database, since

     *  your local names need to be unique.

     *

     *  @param req The request

     *  @param resp The response

     *  @param filename The name of the file you want to download.

     *  @param original_filename The name the browser should receive.

     */

    private void doDownload( HttpServletRequest req, HttpServletResponse resp,

                             String filename, String original_filename )

        throws IOException

    {

        File                f        = new File(filename);

        int                 length   = 0;

        ServletOutputStream op       = resp.getOutputStream();

        ServletContext      context  = getServletConfig().getServletContext();

        String              mimetype = context.getMimeType( filename );



        //

        //  Set the response and go!

        //

        //

        resp.setContentType( (mimetype != null) ? mimetype : "application/octet-stream" );

        resp.setContentLength( (int)f.length() );

        resp.setHeader( "Content-Disposition", "attachment; filename=\"" + original_filename + "\"" );



        //

        //  Stream to the requester.

        //

        byte[] bbuf = new byte[BUFSIZE];

        DataInputStream in = new DataInputStream(new FileInputStream(f));



        while ((in != null) && ((length = in.read(bbuf)) != -1))

        {

            op.write(bbuf,0,length);

        }



        in.close();

        op.flush();

        op.close();

    }
DZone Snippets: servlet code

Example file download servlet
