JSP Tutorials - Herong's Tutorial Examples - Version 4.03, by Dr. Herong Yang
What is EL (Expression Language)?
This section describes what is EL (Expression Language). EL is a Java technology that allows you to use simple expressions to dynamically access data from JavaBeans components in Java based Web application like JSP pages.
What is EL (Expression Language)? EL is a Java technology that allows you to use simple expressions to dynamically access data from JavaBeans components in Java based Web application like JSP pages.
The current version of EL is EL 2.1. You can download EL 2.1 specification document at http://jsp.java.net/spec/jsp-2_1-fr-spec-el.pdf
Here are the main features of EL 2.1 listed in the specification document: The EL is a simple language designed to meet the needs of the presentation layer in web applications. It features:
Here is my understanding of what EL can do for you:
Examples of EL expressions:
${1+1==2} ${1+1} ${1/3} ${1.0/3.0} ${message} ${pageContext.request.method} ${pageContext.request.cookies[0].name} ${quantity*price < 100.0 && country=='USA'}
Tomcat 7 supports EL 2.1. You don't need to download and install anything to use EL 2.1 in JSP 2.1 pages.
Last update: 2012.
Table of Contents
JSP (JavaServer Pages) Overview
Tomcat 7 Installation on Windows Systems
Syntax of JSP Pages and JSP Documents
JavaBean Objects and "useBean" Action Elements
Managing HTTP Response Header Lines
Non-ASCII Characters Support in JSP Pages
►What is EL (Expression Language)?
Literal Data and Named Variables
Basic Operators and Operations
Collection Elements and Object Properties
Expression Examples in Static Text
Expression Examples in Static Text - Result
EL Variables Are pageContext Attributes
Overview of JSTL (JSP Standard Tag Libraries)