August 2002
Intermediate to advanced
688 pages
23h
English
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Declaring a Custom Tag Library
As you know by
now, a
JSP page contains a mixture of JSP elements and template text, in
which the template text can be HTML or XML elements. The JSP
container needs to figure out which is which. It’s
easy for it to recognize the standard JSP elements (because they all
use the jsp namespace prefix), but it needs some
help to find which elements represent custom actions.
That’s where the tag library declaration comes into
play.
Example 7-1 shows a page that uses a custom action from a custom tag library.
Example 7-1. Custom tag library declaration (message.jsp)
<%@ page contentType="text/html" %>
<%@ taglib prefix="ora" uri="orataglib" %>
<html>
<head>
<title>Messages of the Day</title>
</head>
<body bgcolor="white">
<h1>Messages of the Day</h1>
<h2>Deep Thoughts - by Jack Handey</h2>
<i>
<ora:motd category="thoughts" />
</i>
<h2>Quotes From the Famous and the Unknown</h2>
<i>
<ora:motd category="quotes" />
</i>
</body>
</html>This page displays messages from the same collections as the examples
in Chapter 6. The second directive in Example 7-1 is a taglib directive,
which is used to declare a custom tag library. Now,
let’s see what this really means. In order for the
JSP container to use actions from a tag library, it must be able to
do two things: recognize that an element represents a custom action
from a specific library and find the Java class that implements the
custom action logic.
The first requirement -- figuring out which library an action ...
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I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.