Thank you, everyone who replied.
Just one clarification: Boris, did you mean EJBs when you said "Java
Beans"? I would rather not use EJBs. I'm only using a Web container, not
an application server. Also, if what you're referring to are just regular
beans, would they be in a package? I know that is probably a stupid
question, but I have never used beans before, and two developers I've spoken
to in the past have warned me away from EJBs, so when I was planning this
particular project, I was not even considering EJBs.
Jim's suggestion that I package classes and access the methods from the JSPs
sounded like a nice, simple, clean way to do things. His caveat was that it
should be used with caution, and for simple applications. If an application
were not so simple (and right now, the one I'm working on is), would Java
Beans then be the better alternative, if I were able to acquire the
knowledge I needed to use them?
By the way, I read that Taglibs are the next evolution from Java Beans and
that it is better to use them, in a posting on a user list. I belong to a
number of them, and I can't say which one it was. But perhaps my
paraphrasing of what was said there is inaccurate. I did, however, get an
impression from reading it that Tag libraries make using beans obsolete,
though that might not have been the author's intent. I guess that's how
rumours get started. ;-)
I do really appreciate all the knowledge that is being shared on these
lists. I'd be lost without them, and it sure helps to have such
misconceptions cleared up.
Val
- Original Message -
From: "Borislav Iordanov" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Friday, October 18, 2002 12:20 PM
Subject: Re: Database Access Using Tags
Val,
>
> I seem to recall reading on one of the user lists (maybe this one)
that
> using taglibs for connecting to the database was not a good idea, for
> security reasons. The consensus was that it was at least better than
> embedding Java scrptlets in your JSP.
>
The main reason accessing a database through tags is better than Java
scriptlets is that the code is simpler and cleaner. From an
architecture/design point of view, both approaches can be considered
equivalent.
The main reason NOT to access a database in the JSPs is separating
business logic from presentation, given that you consider JSPs as
presentation only technology (strange as it may seem, not everybody
does!). And Model 2 is one approach to that, the most popular one, but
not necessarily the best.
> My question/plea for input here is regarding what I should be using to
> write
> the actual connection in. If tags are not recommended, then should I
be
> using a class, a bean, or a servlet to do that work? I read recently
> (I've
> been doing a LOT of reading) that tags are a replacement for
beans--though
> that sort of conflicts with the point that I read before that tags are
> only
> one step up from using scriptlets. I'm starting to conclude that I
should
> be using a servlet, but I would really appreciate some confirmation
from
> people who are experienced with all this.
>
First, tags are not a replacement for beans, I wonder where you read
that ;) Tags are means for providing abstractions/encapsulating
functionality, be it business logic or presentation related, that is
accessible through an XML-based syntax in a JSP page. That's pretty much
all tags are.
If you want to separate presentation from the business logic, the first
thing you should do is encapsulate the business logic in Java beans.
Those Java beans will work with the database to
access/store/update/delete data. And the JSPs will use those Java beans
to get the information to display.
When it comes to getting input from the end-user and storing it in the
database, you will need to somehow set the bean properties from a
submitted HTML form and tell the bean to write its information to the
database (e.g. something like mybean.insert() or mybean.update). Again,
the Java bean deals with database access and your presentation layer
deals only with the Java bean. Most JSP/Servlets frameworks map
submitted form fields to bean properties automatically. Struts (the most
popular Model 2 framework) does that, even though it limits the types of
your bean properties to primitive Java types. Our product TICL does it
also.
All this is pretty much standard practice...
>
> Also, is it possible/necessary to try to make the structure of the Web
> application object oriented? If I'm using JSP, does that negate the
need
> for creating an object oriented design--does it make that kind of a
> design,
> even though I'm using Java, impossible to really do?
>
It is possible and good practice to have your web application be
object-oriented. However, JSPs make that very difficult, because they
can't be sub-classed. By encapsulating the business logic of your
application in Java beans, you have at least that be object-oriented.
The presentation logic can be made object-oriented
