JavaServer Pages, 3rd Edition

The JSP Standard Tag Library

As I mentioned earlier, the JSTL libraries are implemented based on the same mechanisms as an application-specific custom tag library. The only thing that makes JSTL special is that the functionality and syntax for the JSTL actions are defined by a formal specification, created by the Java Community Process just as the JSP specification itself. This allows vendors to offer implementations of the JSTL actions that are optimized for their JSP container.

JSTL actually consists of five different tag libraries, which minimizes name collisions among actions in different categories. Table 7-2 shows the default URIs and recommended prefixes for all JSTL libraries.

Table 7-2. URI for the JSTL 1.1 libraries

Library	URI	Prefix
Core	http://java.sun.com/jsp/jstl/core	c
XML processing	http://java.sun.com/jsp/jstl/xml	x
I18N formatting	http://java.sun.com/jsp/jstl/fmt	fmt
Database access	http://java.sun.com/jsp/jstl/sql	sql
Functions	http://java.sun.com/jsp/jstl/functions	fn

Warning

If you’ve used JSTL 1.0, note that new URIs are used for JSTL 1.1. The change was, unfortunately, needed to preserve backward compatibility for JSTL 1.0 applications deployed in a JSP 2.0 container because the EL expressions are evaluated by the container instead of the tag handlers starting with JSP 2.0.

The first four libraries contain custom actions of the type described in this chapter. We’ll take a closer look at all of them in the examples in this book.

The last ...