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From "Michael E. Locasto" <loca...@cs.columbia.edu>
Subject Re: Where should i put dynamically generated graphics
Date Fri, 30 Aug 2002 13:21:00 GMT
I can think of a couple of ways offhand:

    -process the request
    -generate your image
    -store your image somewhere (optional)
    - either
        - write the image directly out to the servlet's underlying
outputstream
        as a buffered byte output stream (I don't think PrintWriter would be
appropriate. This would probably also in involve a
"response.setContentType("image/gif"); ... but i've never done this, so I'm
probably wrong.)

    -or-

        -store your image somewhere
        -return html that has a bunch of <img src=""> tags or hyperlinks to
the images
        eg:
        /* get my images! */
  public void doGet(HttpServletRequest request,
                      HttpServletResponse response)
      throws IOException, ServletException {
    /* optionally clean out the temp image directory */
    /* genrt imgs, store in gen_images/username/ under the current context
*/

 response.setContentType("text/html");
 PrintWriter out = response.getWriter();
  out.println( "<html><body>" );
  out.println( "<img src=\"gen_images/username/foo.gif\" >" );
  out.println( "<img src=\"gen_images/username/foo1.gif\" >" );
  out.println( "<img src=\"gen_images/username/foo2.gif\" >" );
  out.println( "</body></html>" );
}

of course, feel free to spruce that html up ;)

hope that helps,
Michael

----- Original Message -----
From: "Felipe Schnack" <felipes@ritterdosreis.br>
To: "Tomcat Users List" <tomcat-user@jakarta.apache.org>
Sent: Friday, August 30, 2002 8:06 AM
Subject: RE: Where should i put dynamically generated graphics


>   How can I return an image from a servlet??
>
> On Thu, 2002-08-29 at 20:05, Sexton, George wrote:
> > It depends. One way I have done it is to have the generator servlet save
it
> > on the session, and have the page the generator servlet writes make a
> > request to a simple servlet that returns the graphic, and then deletes
it
> > from the session.
> >
> > Another way would be to write it to the temp dir. From the Servlet API
Spec:
> >
> > SRV.3.7.1 Temporary Working Directories
> > A temporary storage directory is required for each servlet context.
Servlet
> > containers must provide a private temporary directory per servlet
context,
> > and make
> > it available via the javax.servlet.context.tempdir context attribute.
The
> > objects
> > associated with the attribute must be of type java.io.File.
> >
> > Then, using a servlet mapping request the generated image and have the
> > servlet retrieve the temporary image.
> >
> > I guess that you could make another dir writable to the server, and
store
> > the image in their natively.
> >
> > George Sexton
> > MH Software, Inc.
> > Home of Connect Daily Web Calendar Software
> > http://www.mhsoftware.com/connectdaily.htm
> > Voice: 303 438 9585
> >
> >
> > -----Original Message-----
> > From: Andy Wagg [mailto:andrew.wagg@virgin.net]
> > Sent: 29 August, 2002 4:01 PM
> > To: tomcat-user@jakarta.apache.org
> > Subject: Where should i put dynamically generated graphics
> >
> >
> > Hello
> >
> > I have a web application that generates a gif file that is then
> > subsequently displayed. It expects to find the gif file in the context
> > of the web application. The web app is deployed as a war so obviously
> > the generated files cant be put there. Any suggestions as to where these
> > files could be copied that would be accesible by the browser.
> >
> > Thanks in advance.
> >
> >
> > --
> > To unsubscribe, e-mail:
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> >
> --
>
> Felipe Schnack
> Analista de Sistemas
> felipes@ritterdosreis.br
> Cel.: (51)91287530
> Linux Counter #281893
>
> Faculdade Ritter dos Reis
> www.ritterdosreis.br
> felipes@ritterdosreis.br
> Fone/Fax.: (51)32303328
>
>
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