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From "Joel Sather" <joel.sat...@csu.mnscu.edu>
Subject Re: Where should i put dynamically generated graphics
Date Fri, 30 Aug 2002 15:09:04 GMT

If you want a servlet to write out a GIF stream take a look at this: 
http://www.javaworld.com/javaworld/jw-05-2000/jw-0505-servlets.html

Basically, you have a seperate servlet that generates the GIF.  Then
your real page has a <IMG> tag that references the image display servlet
which sends back a GIF encoded stream.

And of course Google is your friend: 
http://www.google.com/search?hl=en&ie=UTF-8&oe=UTF-8&q=java+servlet+write+gif

-Joel


Joel Sather
email: Joel.Sather@csu.mnscu.edu
phone: 651-649-5789

>>> felipes@ritterdosreis.br 08/30/02 09:53AM >>>
  Yes, I would like the solution where we can write to the servlet
outputstream, but I have no idea how to do it.

On Fri, 2002-08-30 at 10:21, Michael E. Locasto wrote:
> 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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> > >
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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
> >
> >
> > --
> > To unsubscribe, e-mail:
> <mailto:tomcat-user-unsubscribe@jakarta.apache.org>
> > For additional commands, e-mail:
> <mailto:tomcat-user-help@jakarta.apache.org>
> 
> 
> --
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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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