Sunday, May 29, 2005

Investigating Java Tag Libraries

This Memorial Day weekend I decided to spend some time looking into Java Tag Libraries (JTLs) and how to use them with ColdFusion. The how I've been aware of for quite some time of course, but I've never really had the time or strong enough inclincation to start perusing some of the JTL sites out there and try some of this stuff out. There is some seriously cool stuff out there, and dropping it into ColdFusion is extremely simple.

I started by downloading a bunch of the JTLs from The Jakarta Project to give this all a whirl. Tip #1: Even if you drop the JTLs (the jar and tld files specifically, though from what I've messed with you can just use the jar) into your WEB-INF/lib directory, you have to restart ColdFusion for them to get picked up properly. I won't bother telling you how much time I wasted before I gave that a shot, so you're welcome for saving you the hassle. ;-)

The Jakarta stuff is pretty basic but there are some real gems in there. The screen scraping tag, for example, is pretty slick. I'm sure we've all been faced with the task of scraping HTML content to get one particular chunk that we want to, um, "borrow" for our own purposes, and it's usually a matter of making a CFHTTP call and doing some subsequent string manipulation to get what we're after. With the scrape JTL you still have to know what you're looking for, but getting the results is pretty darn simple:

<cfimport taglib="/WEB-INF/lib/taglibs-scrape.jar" prefix="scrp" />

<scrp:page url="" time="20">
<scrp:scrape id="quote" begin="<big>" end="</big>" anchors="yes" />

As you might guess that gives you Macromedia's current stock price as scraped from Yahoo! finance. Sure, not all that earth-shattering, and there are numerous web services that will give you stock quotes, but I thought this was a half-way decent example. Some of the string manipulation functions in the String JTL are slick as well, and there's a LOT of other stuff to check out on the Jakarta page.

The really cool thing is that there are TONS of JTLs out there for the taking. I'm going to peruse all the sites that I can find and see if there are cool ones to share--I've already found some great calendar and image manipulation tags, and I've barely scratched the surface of what's available. And by the example above I hope you can see how easy these are to use.

So this is how a true geek spends Sunday night of Memorial Day weekend. :-) How about the rest of you? Any cool JTLs you use or other experiences along these lines you'd like to share?


You aren't the only geek spending the eve of memorial day doing code!

Some pretty cool stuff man, I'll definately be looking forward to what else you find

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