What I Learned on my Vacation - Part I - WebSphere

What I Learned on my Vacation
Part I - WebSphere

What can I say?  WebSphere works.  It works pretty darned well.  Of course,
it's not without its little pecadillos, but in general it's a pretty solid
product.  Specifically, though, I learned the following:

1. Components.  There are really four basic components to web applications:
HTML, servlets, JavaServer Pages and Java beans (the sort of generic term
for all your other Java support classes).  Each is handled slightly
differently by WebSphere, but they're pretty straightforward once you get
the hang of them.

1A. HTML.  HTML access is controlled completely by the MAP and PASS
directives of your HTTP configuration.  I've also done some preliminary
research on the use of ACLs (Access Control Lists), enough to figure out how
to secure access.  I'll talk about that a little later.

1B. Servlets.  The location of servlets are controlled by the CLASSPATH of
your Web Application.  This is defined in the "advanced" tab of your web
application definition in the webadmin console.  The web application
definition is underneath the servlet engine definition, which is underneath
the application server definition, which is under the node definition.

1C. JavaServer Pages.  I'm still a little fuzzy here.  As close as I can
determine, JavaServer Pages are handled by the web document root of the web
application.  I'm not sure what decides that a given URL is a JSP or a
servlet request, but when a JSP is identified, the path portion of the URL
is appended to the web document root to determine where the JSP is located.

1D. Beans.  I've found that by far the easiest way to handle beans is to put
them in a jar and put the jar in your application classpath.  It's simple,
and as long as your jar files are relatively small, there's no problem.
When you upload a new jar file, WebSphere reloads it automatically.

1E. Overall. I put all my HTML, JSP, and servlets underneath my web document
root.  I use the PASS directive in my HTTP configuration to point the HTML
to the appropriate directory.  That way, all of my components, static or
dynamic, are accessible in the same relative URL structure.


2. Sessions.  Sessions are an interesting concept.  Most importantly,
sessions are meant to be permanent; you're not supposed to go back and forth
between a user session and an anonymous session.  In fact, if you do, you
lose your session variables.  I've been using ACLs to secure my sessions,
and they work quite well.


Anyway, that's Part I of What I Learned on my Vacation.  I'll be giving
another update a little later in the week, I hope.  Are there any particular
areas anyone would like covered?

Joe Pluta
Moderator (well, sort of)

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