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

 About This Book

 JSP (JavaServer Pages) Overview

 Tomcat 7 Installation on Windows Systems

 JSP Scripting Elements

 Java Servlet Introduction

 JSP Implicit Objects

 Syntax of JSP Pages and JSP Documents

 JSP Application Session

 Managing Cookies in JSP Pages

 JavaBean Objects and "useBean" Action Elements

 Managing HTTP Response Header Lines

 Non-ASCII Characters Support in JSP Pages

 Performance of JSP Pages

EL (Expression Language)

What is EL (Expression Language)?

 EL Expression Types and Usage

 Literal Data and Named Variables

 Basic Operators and Operations

 Predefined Implicit Objects

 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)

 JSTL Core Library

 JSP Custom Tags

 JSP Java Tag Interface

 Custom Tag Attributes

 Multiple Tags Working Together

 File Upload Test Application

 Outdated Tutorials

 References

 PDF Printing Version