Core JSTL: Mastering the JSP™ Standard Tag Library

Chapter 2. The JSTL Expression Language

Topics in This Chapter

• Expression Language Overview

• Expressions

• Identifiers

• Operators

• Type Coercion

• Literal Values

• Implicit Objects

• Method Invocation

• EL Expressions in Custom Actions

• Common Mistakes

Although JSTL, as its name implies, provides a set of standard tags, its single most important feature may well be the expression language it defines. That expression language greatly reduces the need for specifying tag attribute values with Java code and significantly simplifies accessing all sorts of application data, including beans, arrays, lists, maps, cookies, request parameters and headers, context initialization parameters, and so on. In fact, the JSTL expression language adds so much value to JSP that it will be ...