Re: loading a servlet in a frame..

From: PerfectDayToChaseTornados (pdtct_at_emailaddress.invalid)
Date: 11/30/04 

Date: Tue, 30 Nov 2004 21:43:32 GMT

"Frances Del Rio" <fdr58@yahoo.com> wrote in message
news:3110teF35rn58U1@uni-berlin.de...
|
|
| PerfectDayToChaseTornados wrote:
| > "Frances Del Rio" <fdr58@yahoo.com> wrote in message
| > news:30o3vpF31rhldU1@uni-berlin.de...
| > |
| > | I have a frameset w/two frames, top frame is form, when user hits
| > | 'submit' I want servlet to load and execute in bottom frame.. if path
| > | to servlet in url-pattern in web.xml is, say /myServlet, and in form I
| > | have action=myServlet, how would I load the servlet into the bottom
| > | frame? thank you.. Frances
| > |
| >
| > Hi Frances, I probably wouldn't use a frame :-) Frames have been
deprecated
| > by W3C & are a real pain for usability (problematic for screen readers
etc).
| > I would either return to the same jsp & have dynamic output in the
bottom
| > part, or have the form as an include & include it in the submission &
result
| > page. To do it using frames would be more complicated as your servlet
would
| > have to return the frameset, you would then need to pick up attributes
in
| > the jsp called from the bottom half of the frameset.
|
| thank you for your response, TornadoChaser... I had not seen it until
| now.. you responded also to my other post, about how to do this (have
| return stuff print on same window..) w/a jsp.. but I have not been able
| to make that work.. I still want to do it, I'm learning and this app is
| more a learning exercise than anything else.. I did manage to load the
| servlet into another frame (frames -- deprecated? sorry, I think that's
| ridiculous, there's lots of cool stuff you can do w/frames if you use
| them right..) check it out..
|
| www.francesdelrio.com/hamlet..
|
| it turns out it was quite easy, not a java question at all, all I had to
| do was put "target='main'" (name of frame) in form tag to indicate I
| want results of form submission to show up in other frame.. had no idea
| until now you could put a target attr in form tag.. you never finish
| learning little things.... ;)
|
| I still want to make a jsp version of this (again, this is a learning
| exercise..) so: maybe I can now still try do what you said and do it all
| on one frame in jsp? (the way it works now though, in servlet version
| that loads in another frame, when user hits 'reload' it gets 'cleaned
| up' and return disappears and bottom frame returns to being empty..
| could I do this effect in jsp? w/everyting in same frame?) here's
| source code of current servlet..
|
| www.francesdelrio.com/java/hamlet.html
|
| am trying to figure out how to best 'convert' this to jsp.. the
| confusing part to me about what you sent me was how jsp 'reads' from
| servlet.. this part..
|
| <% String myWord = (String) request.getAttribute("yourattributename");
| if(myWord == null){
| myWord = "";
| } %>
|
| how does jsp here know what servlet to read from? I put everything you
| wrote that time in a one-pg word file, for easier ref.. in case you
| forgot what you wrote.. www.francesdelrio.com/java/how-to.doc.. thank
| you again very much.. Frances
|
Hi Frances,

The Servlet forwards to the jsp. So you still submit to a Servlet, the
Servlet does the processing & then forwards the request to the jsp, the jsp
then accesses the attributes you put in the request or session. It is best
to keep as much code out of jsps as possible & to do your processing in a
Servlet.

If you are still insistent on using frames ;-) then you will need to set the
attributes with session scope before you return the frameset, as the
frameset then makes a new HTTP request for each contained frame. You can
then access the attributes in the jsp, but you will probably also want to
remove them from the session after using them with
session.removeAtrribute(attname).

As for includes, you can include jsp content in other jsps, see these links
here for details
http://java.sun.com/products/jsp/syntax/1.1/syntaxref1112.html
http://java.sun.com/products/jsp/syntax/1.1/syntaxref117.html#8772

This is also an excellent jsp syntax ref you can print out.
http://java.sun.com/products/jsp/syntax/1.2/card12.pdf

If I understand you correctly you want your 'do it again' button to clear
all of the output on the page. You can do that by submitting to the Servlet
& clearing the variables. If they are request scope anyway, just returning
the page will have cleared the variables.

With regard to frames, I agree they can be useful. But they can also be over
used & lead to inelegant solutions. But the fact is they are deprecated & do
cause problems for people with screen readers. I try to avoid them now if
possible & look for other solutions. 99% of the time there are more elegant
ways to achieve the same thing :-)

HTH :-) 

-- 
-P
"Programs that are hard to read are hard to modify.
  Programs that have duplicated logic are hard to modify.
  Programs with complex conditional logic are hard to modify"
( Kent Beck)