Milt,
I was incorrect, as you point out, in my use of "servlets" when I should
have just stated "server side Java in the form of beans and classes".
Shash
Milt Epstein wrote:
>
> I wanted to comment on some of the things in the response below -- I
> haven't really used JSP, but some of the things seem incorrect, given
> my understanding of it. Of course, if some of my comments are
> incorrect, I hope someone corrects them.
>
> On Wed, 19 Jan 2000, Shash Chatterjee wrote:
>
> > Pere Soler Rubi wrote:
> > >
> > > Hi to all,
> > > We are thinking about designe of a web site. We don't know what are
> > > the advantages that JSP offers. We have read all the Sun's stuff, but
> > > we need some in depth information. Our questions are:
> >
> > I have been playing with JSP lately. The advantage is that it allows
> > you to separate the mechanics of HTML (or, other display client-side
> > presentation technology) from the actual logic and data of the
> > servlet. That is, you can have the same servlet serving up the
> > data, but depending on how the JSP page that uses the servlet is
> > written, the presentation can be different. Or, looking at it
> > another way, you can decide to change the "look" of your pages/site
> > without having to change/recompile the server. Yet another way, you
> > can use the same servlet in three different places on your website
> > or on three different sites and have the output look entirely
> > different.
>
> It's true that JSP does help in terms of separation of display and
> logic/data, but it doesn't do it completely. More importantly, you
> can't use JSP to present the output of the same servlet differently --
> each JSP is compiled into a servlet, so there is a one-to-one
> correspondence between JSP and servlet. (Although if you have other
> classes, like beans or business logic, you could have the JSP present
> the output of those differently.)
>
> > > * Does JSP overload the server ?
> >
> > That I don't know from experience, but the answer probaly is that it
> > depends on how much the JSP page changes, thereby requiring
> > regeneration of the servlet and a recompilation. On a JSP page that
>
> Right, but remember, this is only done once per change, no matter how
> many times it is requested. And I believe some servlet engines
> allow/will allow pre-compiling of changed pages so that they don't
> have to wait for the first request.
>
> > does not change, there is some extra overhead in reading the page,
> > parsing it and determining which servlet to invoke, but it is
>
> Well, as I said above, each JSP is compiled into a servlet, so after
> that, there is no parsing and determining which servlet to invoke
> necessary, it is the same as invoking a servlet directly (a check does
> have to be made that the JSP hasn't changed, but I suppose there could
> be an option to skip this check -- in conjunction with the above
> pre-compilation option).
>
> > minimal when compared to the added overhead of actually compiling
> > the servlet. Overall, though, this per-page overhead would get
> > multiplied by the number of JSP-page accesses and so the answer
> > depends on how intensely the website is accessed. I run
> > Redhat-6.1/Apache-1.3.9/JServ-1.1b3/GNUJSP-1.0 on a PIII/500/128MB
> > box at home that isn't loaded at all (i.e. not connected to the
> > "net"), and there is an appreciable delay the first time the JSP
> > page is compiled. You can't really call this "loading", it is a
> > "delay" (and understandable if you think about what is happening
> > behind the scenes).
> [ ... ]
>
> Milt Epstein
> Research Programmer
> Software/Systems Development Group
> Computing and Communications Services Office (CCSO)
> University of Illinois at Urbana-Champaign (UIUC)
> [EMAIL PROTECTED]
>
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