JSP Web-Development [newbie]

P

pmz

Dear Group,

1. At the beginning I'd like to apologize you for any mistakes or
misunderstood's, which might occur in message below, but I'm a quite
beginner in JSP so maybe some of my problems aren't really problems ;)
My Java knowledge is intermediate, but the structures of JSP or JSF or
any other frameworks is pretty bad, but I do not have any idea how to
start.

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.

3. What I've done in PHP, is quite simple structural solution, which
looked like following:

mainFile {
switch( __mainArgument from _GET ) {
case "myPlugin":
include "myPlugin.inc.php";
break;
/// And so on, and so on
}
}

The problem is, that the switch() java statement is not supporting
Strings - okay - so I'm not able to such as above. That does not
matter at all, because I thought that I'll just divide my website into
subfolders, such as:

Web Pages \
\index.jsp
\news\index.jsp
\users\index.jsp
\requests\index.jsp

That sollution is quite okay for me - any other suggestions? - but 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.

Shall I use the mod_rewrite (ie. /any_here/index.jsp > /index.jsp?
module=any_here - then the request parameter fetching is much easier.

I do not need pure explanations for my problems, because I'm able to
learn it by my self. Unfortunately, while I've been googling for some
tutorials "How create a JSP complex website?", I found some stupid
documents, which just describe how to build a "Hello World"
application without any complex elements (such as site modules, etc.).
Okay, I'm able to browse manuals delivered by Sun or anyone else, but
also, it's pure javadoc, with no solution proposals.

Thank you VERY much for help!

All the best,
Przemek M. Zawada
 
C

Chris Riesbeck

Dear Group,

1. At the beginning I'd like to apologize you for any mistakes or
misunderstood's, which might occur in message below, but I'm a quite
beginner in JSP so maybe some of my problems aren't really problems ;)
My Java knowledge is intermediate, but the structures of JSP or JSF or
any other frameworks is pretty bad, but I do not have any idea how to
start.
Click to expand...

Personally, I prefer JSTL over straight JSP, to reduce jumping back and
forth between HTML and Java syntax. So iteration over a collection is

<ul>
<c:forEach var="item" items="${myObj.thingies}">
<li><c:eek:ut value="${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.
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.
Click to expand...

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. So you could have

webapp/
pages/
jsp files
styles/
css files
images/
...
WEB-INF/
classes/
...
...

and other flatter or more nested structures as you choose.
3. What I've done in PHP, is quite simple structural solution, which
looked like following:

mainFile {
switch( __mainArgument from _GET ) {
case "myPlugin":
include "myPlugin.inc.php";
break;
/// And so on, and so on
}
}

The problem is, that the switch() java statement is not supporting
Strings - okay - so I'm not able to such as above.
Click to expand...

I don't know PHP so I don't know what mainArgument is, but if there's a
URL parameter thing for selecting what to include, e.g.,
/myApp?thing=myPlugin, then you could do something like that with this JSTL:

<c:choose>
<c:when test='${param.thing == "myPlugin"}'>
<jsp:include page="myPlugin.jsp" />
</c:when>
...
<c:eek:therwise>
<jsp:include page="myDefault.jsp" />
</c:eek:therwise>
</c:choose>

Whether that's a good way to do this is not for me to say.

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.
Click to expand...

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.

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:eek:ut 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. 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.
 
P

pmz

Personally, I prefer JSTL over straight JSP, to reduce jumping back and
forth between HTML and Java syntax. So iteration over a collection is

   <ul>
     <c:forEach var="item" items="${myObj.thingies}">
        <li><c:eek:ut value="${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.
Click to expand...

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.

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.

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).

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. So you could have

   webapp/
     pages/
       jsp files
     styles/
       css files
     images/
        ...
     WEB-INF/
       classes/
         ...
       ...

and other flatter or more nested structures as you choose.
Click to expand...

As you said, my directory tree looks like the following:
\Project Name
\Web Pages
\META-INF
\WEB-INF
\jNLC
\users\add.jsp
\users\edit.jsp
\styles\(*.css)|(*.js)
\index.jsp
\Source Packages
\Libraries
\Configuration Files

That's the way NetBeans shows it to me. I suppose that's okay?
I don't know PHP so I don't know what mainArgument is, but if there's a
URL parameter thing for selecting what to include, e.g.,
/myApp?thing=myPlugin, then you could do something like that with this JSTL:

   <c:choose>
     <c:when test='${param.thing == "myPlugin"}'>
       <jsp:include page="myPlugin.jsp" />
     </c:when>
     ...
     <c:eek:therwise>
       <jsp:include page="myDefault.jsp" />
     </c:eek:therwise>
   </c:choose>

Whether that's a good way to do this is not for me to say.
Click to expand...

Yes! That the way I'd like to work! (In fact, the mainArgument is
requestParameter, string valued)
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:
Click to expand...
/// 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>
Click to expand...
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.
Click to expand...

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.

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:eek:ut 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. 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...

Javaworld, IBM and Sun/Oracle are reliable sources.
Click to expand...

Okay! I'll do it. Now I know what should I look for directly. These
are base problems, I know, but I thank you for enlightening me the
bases.

All the best,
Przemek M. Zawada
 
P

pmz

Few more knowledge leaks:

1. Let's say I have a sample jsp file, ie:

<anyJspTag>
<set parameter a="type1" />
<jsp:include page="mypage.jsp" />
</anyJspTag>

Question: Is it possible to access the "a" parameter (with defined or
dynamic) value in the mypage.jsp (which for example contains the
<c:choose /> related to "a" parameter ?) If yes, then I'd be able to
choose some sectors of mypage.jsp which should be visible regarding to
request parameters - true?

2. I'd like to build a menu with submenus from standalone XML file -
how shall I start? How ppl do it?

I need to change my php-thinking into jsp-thinking - that's quite
difficult, but I'm trying.

Thank you :)

Przemek M. Zawada
 
M

markspace

The following contains a lot of opinions, as opposed to facts. Caveat
emptor.
mainFile {
switch( __mainArgument from _GET ) {
case "myPlugin":
Click to expand...

I'd regard this as somewhat suspect even in PHP. It requires URLs like
"http://example.com/?__mainArgument=myPlugin" and that looks kinda ugly
to the user. I'd rather supply the user with something like
"http://example.com/myPlugin" and use mod-rewrite to redirect that if
needed, thus eliminating any need to code it at all.

You can't use mod-rewrite in Java, because War files aren't visible to
Apache. All the Java files are contained within one archive which isn't
something Apache can read. So Java provides it's own way to do this,
again with out writing code, like what mod_rewrite provides.

In the WEB-INF/web.xml file, you'd bind a pattern to a name, like this:

<servlet-mapping>
<servlet-name>MainPlugIn</servlet-name>
<url-pattern>/myPlugin</url-pattern>
</servlet-mapping>

That replaces mod_rewrite, and maps the url pattern after your hostname
to the name MainPlugIn. Now you have to do one more thing to map the
name MainPlugIn to some code.

<servlet>
<servlet-name>MainPlugIn</servlet-name>
<servlet-class>myplugin/plugin.jsp</servlet-class>
</servlet>

You may have to play with the servlet-class a bit, I'm not 100% sure
that it works exactly like that.

This is a very powerful feature, and you should use it as much as
possible. In particular, it allows you to change any url so that it
calls any code in your app, and you don't have to search and modify your
code to do it. Just change a config file and it works.

The web.xml file itself can be a pain, but if you get a good IDE like
NetBeans or Eclipse, they'll do most of the work for you. That reminds
me: if you're looking for good tutorials, you could try the how-to's
for the IDEs. NetBeans has several that will show you how to build a
moderately complex web app.

<http://netbeans.org/kb/trails/java-ee.html>

You should probably avoid the EJB stuff (that's really complex) and JSF
- Java Server Faces - and the other stuff under Web Frameworks can be
skipped at first. Don't want to over load you with too much. Also
check out the Other Tutorials section and the Web Blogs might be a
useful source on info for you.

Web Pages \
\index.jsp
\news\index.jsp
\users\index.jsp
\requests\index.jsp

That sollution is quite okay for me - any other suggestions? - but I
Click to expand...


Also, use the fact that WEB-INF is private to hide JSPs and servlets
that you don't want the user calling directly.

Web Pages \
index.jsp
other-public.jsp
WEB-INF \
private.jsp
myplugin \
plugin.jsp
etc.
css \
public.css
images \
public.jpg

Etc.
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]
Click to expand...


Due to the servlet-mapping above, naming everything "index.jsp" is not
needed in a Java app. This would actually go to a servlet or JSP named
\%s, not \%s\index.jsp.

Anything that's extra on the path gets added as an attribute. <%
request.getPathInfo(); %> will return the extra path string. There's
probably an EL variable that returns the extra path string as well, but
I don't recall it offhand.

Anyway, use the request path and context path to figure out stuff that
depends on the path, but mostly you want to direct your URLs to a
servlet that already knows what to do with out a lot of "figuring out."


Shall I use the mod_rewrite (ie. /any_here/index.jsp > /index.jsp?
module=any_here - then the request parameter fetching is much easier.
Click to expand...

Again, I don't think mod-rewrite is going to help you with JSPs and
servlets.

Also, try reading the servlet specifications, it's are surprisingly
readable.

<http://jcp.org/aboutJava/communityprocess/final/jsr154/index.html>

Java EE 6 Tutorial.

<http://download-llnw.oracle.com/javaee/6/tutorial/doc/>
 
C

Chris Riesbeck

Few more knowledge leaks:

1. Let's say I have a sample jsp file, ie:

<anyJspTag>
<set parameter a="type1" />
<jsp:include page="mypage.jsp" />
</anyJspTag>

Question: Is it possible to access the "a" parameter (with defined or
dynamic) value in the mypage.jsp (which for example contains the
<c:choose /> related to "a" parameter ?) If yes, then I'd be able to
choose some sectors of mypage.jsp which should be visible regarding to
request parameters - true?
Click to expand...

Either of the following works to pass info to an included page:

<c:set var="someVar" value="..." scope="request" />
<jsp:include page=... />

- inside the included page, use ${someVar} to access the value
- the scope is needed; by default, variables are page scope, i.e.,
not shared across pages

or

<jsp:include page=...>
<jsp:param name="someVar" value="..." />
</jsp:include>

- inside the included page, use ${param.someVar} to access the value
2. I'd like to build a menu with submenus from standalone XML file -
how shall I start? How ppl do it?
Click to expand...

JSTL has XML processing forms but I've not used them. A JSTL quick
reference I quite like (http://www.cs.uiowa.edu/~slonnegr/wpj/jqr.pdf)
gives this example:

<c:import var="rss"

url="http://servlet.java.sun.com/syndication/rss_java_highlights-PARTNER-20.xml"/>
<x:parse var="news" xml="${rss}"/>

which puts parsed XML data into "news".

I need to change my php-thinking into jsp-thinking - that's quite
difficult, but I'm trying.
Click to expand...

Some of it is going to model-view-controller which is a more general
concept than Java. Even though JSTL has some nice SQL tags, I don't use
them because it puts too much business logic in the presentation layer.
 
W

Wojtek

pmz wrote :
Dear Group,

1. At the beginning I'd like to apologize you for any mistakes or
misunderstood's, which might occur in message below, but I'm a quite
beginner in JSP so maybe some of my problems aren't really problems ;)
My Java knowledge is intermediate, but the structures of JSP or JSF or
any other frameworks is pretty bad, but I do not have any idea how to
start.

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.

3. What I've done in PHP, is quite simple structural solution, which
looked like following:

mainFile {
switch( __mainArgument from _GET ) {
case "myPlugin":
include "myPlugin.inc.php";
break;
/// And so on, and so on
}
}

The problem is, that the switch() java statement is not supporting
Strings - okay - so I'm not able to such as above. That does not
matter at all, because I thought that I'll just divide my website into
subfolders, such as:

Web Pages \
\index.jsp
\news\index.jsp
\users\index.jsp
\requests\index.jsp

That sollution is quite okay for me - any other suggestions? - but 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.
Click to expand...

You need to do a paradigm shift.

In PHP you include files selectively mostly for performance reasons, as
you do not want the interpreter parsing logic which will not be used
during that page hit.

Using Java, the JSP is a servlet which is compiled once into a class,
then used after that. In most cases the JSP servlet class remains in
server memory so load times are very fast.

Because the JSP is compiled once as a whole, it is impossible to
selectively include files for each page hit.

If the included files have differing processing logic, then you really
should move that logic into the application as classes and servlets. A
JSP should only contain enough logic to support display requirements
not processing requirements.
 
A

Arne Vajhøj

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.

3. What I've done in PHP, is quite simple structural solution, which
looked like following:

mainFile {
switch( __mainArgument from _GET ) {
case "myPlugin":
include "myPlugin.inc.php";
break;
/// And so on, and so on
}
}

The problem is, that the switch() java statement is not supporting
Strings - okay - so I'm not able to such as above.
Click to expand...

You could use if statements.

But you really should use a servlet instead of a JSP page
to do that.

Which could either be your own servlet or one of the many
MVC web frameworks.
> That does not
matter at all, because I thought that I'll just divide my website into
subfolders, such as:

Web Pages \
\index.jsp
\news\index.jsp
\users\index.jsp
\requests\index.jsp

That sollution is quite okay for me - any other suggestions?
Click to expand...

I do not see the correlation with the previous section,
but it seems OK.
> - but 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.
Click to expand...

If you want to do that then I think you should look at something
like Tiles.

Shall I use the mod_rewrite (ie. /any_here/index.jsp> /index.jsp?
module=any_here - then the request parameter fetching is much easier.
Click to expand...

I do not see any need for mod_rewrite.

Arne
 
A

Arne Vajhøj

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.
Click to expand...

Maybe your servlet container comes with JSTL support.

Otherwise you can download an implementation like:
http://tomcat.apache.org/taglibs/standard/
and put the two jar files in WEB-INF/lib.

Then you need to put taglib definitions in top of your JSP pages.

Like:

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.

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?
Click to expand...

You should use a servlet for that.

JSP page = View
Servlet = Control

Arne
 
A

Arne Vajhøj

Few more knowledge leaks:

1. Let's say I have a sample jsp file, ie:

<anyJspTag>
<set parameter a="type1" />
<jsp:include page="mypage.jsp" />
</anyJspTag>

Question: Is it possible to access the "a" parameter (with defined or
dynamic) value in the mypage.jsp (which for example contains the
<c:choose /> related to "a" parameter ?) If yes, then I'd be able to
choose some sectors of mypage.jsp which should be visible regarding to
request parameters - true?
Click to expand...

The syntax is a bit different.

http://java.sun.com/products/jsp/tags/11/syntaxref1112.html

Arne
 
A

Arne Vajhøj

The following contains a lot of opinions, as opposed to facts. Caveat
emptor.


I'd regard this as somewhat suspect even in PHP. It requires URLs like
"http://example.com/?__mainArgument=myPlugin" and that looks kinda ugly
to the user. I'd rather supply the user with something like
"http://example.com/myPlugin" and use mod-rewrite to redirect that if
needed, thus eliminating any need to code it at all.

You can't use mod-rewrite in Java, because War files aren't visible to
Apache. All the Java files are contained within one archive which isn't
something Apache can read. So Java provides it's own way to do this,
again with out writing code, like what mod_rewrite provides.
Click to expand...

Why would:
Apache HTTPD with mod_rewrite -> Apache Tomcat
not work?
In the WEB-INF/web.xml file, you'd bind a pattern to a name, like this:

<servlet-mapping>
<servlet-name>MainPlugIn</servlet-name>
<url-pattern>/myPlugin</url-pattern>
</servlet-mapping>

That replaces mod_rewrite, and maps the url pattern after your hostname
to the name MainPlugIn. Now you have to do one more thing to map the
name MainPlugIn to some code.

<servlet>
<servlet-name>MainPlugIn</servlet-name>
<servlet-class>myplugin/plugin.jsp</servlet-class>
</servlet>

You may have to play with the servlet-class a bit, I'm not 100% sure
that it works exactly like that.

This is a very powerful feature, and you should use it as much as
possible. In particular, it allows you to change any url so that it
calls any code in your app, and you don't have to search and modify your
code to do it. Just change a config file and it works.
Click to expand...

I don't think that provides nearly as much functionality as mod_rewrite
when it comes to smart rewrites.

Arne
 
A

Arne Vajhøj

Personally, I prefer JSTL over straight JSP, to reduce jumping back and
forth between HTML and Java syntax. So iteration over a collection is

<ul>
<c:forEach var="item" items="${myObj.thingies}">
<li><c:eek:ut value="${item}" /></li>
</c:forEach>
</ul>

instead of

<ul>
<% for (Object item : myObj.getThingies()) { %>
<li><%= item %></li>
<% } <%>
</ul>
Click to expand...

Very good advice.

With newer versions:

<li><c:eek:ut value="${item}" /></li>

can even be written as:

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. So you could have

webapp/
pages/
jsp files
styles/
css files
images/
...
WEB-INF/
classes/
...
...

and other flatter or more nested structures as you choose.
Click to expand...

JSP pages in WEB-INF are not directly accessible, but they can
be used from servlet / action classes.

Some even consider that good practice.

I don't agree, but ...

Arne
 
L

Lew

"Group" isn't exactly the right term here. It's a Usenet forum.


Excellent advice.

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.
Click to expand...

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.
Click to expand...

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.
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?
Click to expand...

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.

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.


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.
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:
Click to expand...
/// 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>
Click to expand...
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.
Click to expand...
Click to expand...
Chris said:
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.
Click to expand...
Click to expand...

We-e-e-ll, that all depends.

a.k.a. "MVC". Wikipedia is a decent source for an introduction to this concept.

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/guid...prise_applications_2e/web-tier/web-tier5.html>
 
M

markspace

Arne said:
Why would:
Apache HTTPD with mod_rewrite -> Apache Tomcat
not work?
Click to expand...

Did you try it? Did it work? I'm honestly interested to know, it never
occurred to me that it might work.

I don't think that provides nearly as much functionality as mod_rewrite
when it comes to smart rewrites.
Click to expand...

What if Apache isn't your web server?
 
L

Lew

....
What if Apache isn't your web server?
Click to expand...

In general a good question. In the OP's particular case it's pretty clear
they're in control of the environment and can choose it to be.
 
M

markspace

Lew said:
....


In general a good question. In the OP's particular case it's pretty
clear they're in control of the environment and can choose it to be.
Click to expand...


Seems like a good way to get bit if you ever export the web app to a
different environment. Sure, Apache is very popular and you can just
spec the app that way to customers, but it's also just one more thing to
deal with manually (the mod_rewrite stuff) that doesn't need to be, I
suppose.
 
A

Arne Vajhøj

Did you try it? Did it work? I'm honestly interested to know, it never
occurred to me that it might work.
Click to expand...

I have not tried it, but I would expect it to work.

If used with PHP it is:

---(original request)-->mod_rewrite--(modified
request)-->mod_php---->PHP scipt

With Tomcat it should be:

---(original request)-->mod_rewrite--(modified request)-->mod_jk--(AJP
protocol)-->Tomcat

Given the functionality of mod_rewrite it must be executed before
the real mod's and be rather independent of what those mod's do.

At least that is my expectation.
What if Apache isn't your web server?
Click to expand...

The using an Apache module like mod_rewrite is obviously not an option.

Arne
 
L

Lew

Seems like a good way to get bit if you ever export the web app to a
different environment. Sure, Apache is very popular and you can just
spec the app that way to customers, but it's also just one more thing to
deal with manually (the mod_rewrite stuff) that doesn't need to be, I
suppose.
Click to expand...

It is not uncommon to spec requirements for an app to run. And some kinds of
portability are overrated. I'm not necessarily speaking in favor of
mod_rewrite, but I do think httpd is an awesome product and one should not be
ashamed or fearful of basing an application on it.

And there are hundreds of products on the market that already spec it as part
of their product. Ever hear of LAMP?
 
T

Tom Anderson

Also, use the fact that WEB-INF is private to hide JSPs and servlets
that you don't want the user calling directly.

Web Pages \
index.jsp
other-public.jsp
WEB-INF \
private.jsp
myplugin \
plugin.jsp
etc.
css \
public.css
images \
public.jpg

Etc.
Click to expand...

Nice trick! I didn't know that one. You could hide config files and so on
like this too.

tom
 
T

Tom Anderson

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?
Click to expand...

No. You're doing this all wrong. Or rather, you're doing it all PHP, which
in JSP means wrong.

Use separate pages for the different pages, and a tag file to define the
common structure:

http://www.oracle.com/technology/sample_code/tutorials/jsp20/tagfiles.html

A tag file is the analog of a framework method in code; it can write a
load of HTML, but can also invoke fragments passed by the original
invoker.

For example, given a tag file like this (call it main.tag):

<%@ attribute name="content" required="true" fragment="true" %>
<html>
<body>
<h1>PMZ's SUPER SITE</h1>
<jsp:invoke fragment="content"/>
</body>
</html>

You could write a JSP like this:

<%@ taglib prefix="mytags" tagdir="/WEB-INF/tags" %>
<mytags:main>
<jsp:attribute name="content">
<p>Some content.</p>
</jsp:attribute>
</mytags:main>

This would invoke the main.tag to build the page structure, which would
then call down to the fragment defined in the JSP. You can have multiple
fragments, and also use normal content of the tag via <jsp:doBody/>.

tom
 

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