1  
   2    /**
   3       *  Sends a file to the ServletResponse output stream.  Typically
   4       *  you want the browser to receive a different name than the
   5       *  name the file has been saved in your local database, since
   6       *  your local names need to be unique.
   7       *
   8       *  @param req The request
   9       *  @param resp The response
  10       *  @param filename The name of the file you want to download.
  11       *  @param original_filename The name the browser should receive.
  12       */
  13      private void doDownload( HttpServletRequest req, HttpServletResponse resp,
  14                               String filename, String original_filename )
  15          throws IOException
  16      {
  17          File                f        = new File(filename);
  18          int                 length   = 0;
  19          ServletOutputStream op       = resp.getOutputStream();
  20          ServletContext      context  = getServletConfig().getServletContext();
  21          String              mimetype = context.getMimeType( filename );
  22  
  23          //
  24          //  Set the response and go!
  25          //
  26          //
  27          resp.setContentType( (mimetype != null) ? mimetype : "application/octet-stream" );
  28          resp.setContentLength( (int)f.length() );
  29          resp.setHeader( "Content-Disposition", "attachment; filename=\"" + original_filename + "\"" );
  30  
  31          //
  32          //  Stream to the requester.
  33          //
  34          byte[] bbuf = new byte[BUFSIZE];
  35          DataInputStream in = new DataInputStream(new FileInputStream(f));
  36  
  37          while ((in != null) && ((length = in.read(bbuf)) != -1))
  38          {
  39              op.write(bbuf,0,length);
  40          }
  41  
  42          in.close();
  43          op.flush();
  44          op.close();
  45      }