Beginning JavaServer Pages™

Appendix C. JSTL Reference

The Java Standard Tag Library (JSTL) is a standardized collection of custom tags. It has a number of tags for common tasks such as iterating through lists, interacting with databases, handling XML data, formatting data, and much more.

The latest version of JSTL (at the time of writing) is 1.1. An implementation of JSTL can be downloaded from the Apache Jakarta Web site (http://jakarta.apache.org/).

JSTL consist of four sets of tags and a library of functions, grouped according to their functionality:

• JSTL core tags

• JSTL XML tags

• JSTL formatting tags

• JSTL SQL tags

• JSTL functions

JSTL Core Tags

The JSTL core tag library contains tags that deal with flow control in JSP pages, iterating over collections, evaluating expressions, and importing resources.

Before using the core tag library, the following directive needs to be added to the JSP page:

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>

The equivalent XML syntax for this directive is as follows:

<jsp:directive.taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" />

The following table summarizes the JSTL core tags.

Tag Name	Description
catch	Catches any Throwable exception that occurs in the body of the tag
choose	Provides conditional operation and allows for choosing between mutually exclusive options
if	Provides conditional operation
import	Imports a resource specified by a URL and exposes it to the page, variable, or reader
forEach	Iterates over collections
forTokens	Iterates over tokens
out	Outputs expressions ...