Re: JSP Web-Development [newbie]
pmz wrote:
"Group" isn't exactly the right term here. It's a Usenet forum.
Chris Riesbeck wrote:
Personally, I prefer JSTL over straight JSP, to reduce jumping back and
Excellent advice.
forth between HTML and Java syntax. So iteration over a collection is
<ul>
<c:forEach var="item" items="${myObj.thingies}">
<li><c:out value="${item}" /></li>
</c:forEach>
</ul>
instead of
<ul>
<% for (Object item : myObj.getThingies()) { %>
<li><%= item %></li>
<% }<%>
</ul>
With more nesting, those separated braces get annoying fast.
Besides, you aren't supposed to put Java code ("scriptlet") directly in JSPs,
as a matter of practice.
That's true and I think I'll try using those, too. My question is,
shall I make any changes in environment of NetBeans to use JSTL? File
extensions? Additional libraries? But okay, if it's obvious and I'll
find it by googling for it, ignore my questions.
NetBeans Web project "Properties" has an entry for "Libraries", and a button
to "Add Library", and one built-in choice there is JSTL. NB then
automagically adds the jstl.jar JAR to your application.
The base idea is: Let's say I have few packages which contain database
access, data management and some others, which are pure Java objects,
without any HTML stuff. What I want to achieve, is to work over the
data I fetch or I submit in JSP pages.
Read about "Expression Language" (EL) in the Java EE tutorial and other sources.
<http://download.oracle.com/javaee/6/tutorial/doc/gjddd.html>
There's a decent chapter in the Java EE 5 tutorial also,
<http://download.oracle.com/javaee/5/tutorial/doc/bnahq.html>
plus its "Web Tier" chapter covers servlets and JSP.
<http://download.oracle.com/javaee/5/tutorial/doc/bnadp.html>
I'd like to have ONE default JSP page (which obviously contains a
webpage main layout - styles, scripts, tables, images, etc.). In few
places I have some dynamical stuff (such as parameter-regarded menu
display or also parameter-regarded body display).
Shall I use you<c:choose/> method for further inclusion of required
jsp-sub-pages?
It's not his, or mine, but JSTL's. That's one way but not the only way,
perhaps not even the best way.
There's a <jsp:include>
<http://download.oracle.com/javaee/5/tutorial/doc/bnajb.html>
and a <jsp:forward> tag.
<http://download.oracle.com/javaee/5/tutorial/doc/bnajc.html>
2. I'm trying to build bit complex website based on JSP (which I've
done a lot in PHP, so the main idea of website engineering is quite
common for me), but I a bit confused about the architecture/structure
of a JSP webpage building. The problem is, I'm not able to imagine in
my mind, how the architecture (directory structure) should be found,
how do I divide the template files, the engine core, etc.
JSP isn't exactly a "template" framework as you might think of it, but close
enough for now.
Usually you have backing Java logic implemented as straight-up Java objects
accessed from page/session/application context using <jsp:useBean> and,
primarily, EL. The backing logic handles the "model" aspect - business logic,
interaction with back-end data stores and such, feeding the "view" aspect that
the JSPs embody.
Chris Riesbeck wrote:
You can do almost anything, but don't put pages and other user-viewable
items under WEB-INF. WEB-INF is for libraries, class files, and XML
configuration files.
And JSP fragments (.jspf files) and other resources that the user should not
access directly but only under control (e.g., <jsp:include>) of your logic.
pmz wrote:
I was wondering what about dynamic elements, which are visible in any
index.jsp (and \*\index.jsp) file? Let me show it on an example:
/// index.jsp
<html>
<body>
<div>
[DEPEND ON \%s\index.jsp CONTENT HERE] [1]
</div>
<div>
[DEFAULT CONTENT of \%s\index.jsp] [2]
</div>
</body>
</html>
The [2] position is quite simple, because it might be defined directly
in my file, but what if I include in [1] position a file, which is
also included in base index.jsp (ROOT)? There should be a submenu
display, which should display menu items regarding to the module
selected.
Chris Riesbeck wrote:
This may be a paradigm difference with PHP. In JSP, you don't do a lot
of including of other JSP files. That's mostly for common blocks of
HTML/JSP code, like a navigation bar.
We-e-e-ll, that all depends.
Most of the dynamic content is created by the use of c:forEach and
c:choose and so on, along with Java object containers, like this:
<p>Welcome,<c:out value="${user.fullName}" />!</p>
where user is a session attribute set up by a backend Java application.
JSP/JSTL/JSF are used for front-end display -- the view and controller
in model-view-controller.
a.k.a. "MVC". Wikipedia is a decent source for an introduction to this concept.
The more complex model logic is done in Java.
Google for Java JSTL best practices and you'll get sites like
<http://www.oracle.com/technetwork/articles/javase/servlets-jsp-140445.html>
Javaworld, IBM and Sun/Oracle are reliable sources.
IBM Developerworks is very worthy, too.
Google for Java's "Model 2" architecture for a simplified MVC architecture.
It's mentioned in the link Chris Riesbeck provided. Also here:
<http://en.wikipedia.org/wiki/Model_2>
<http://java.sun.com/blueprints/guidelines/designing_enterprise_applications_2e/web-tier/web-tier5.html>
--
Lew