Chapter 2 - JSTL Basics

Abstract

This chapter covers some of the JavaServer Pages Standard Tag Library (JSTL) basics that are common throughout the various tag libraries and actions. The concepts involved with the scopes of JavaServer Pages (JSP) are important when dealing with JSTL actions. So, it is important to spend some time making sure everyone has a complete understanding of the available scopes: page, request, session, application, and what they mean in terms of an object's accessibility. Exceptions and errors can happen just about anywhere, so some of the rules that are applied to handling exceptions within actions are being looked at. Because JSTL supports an expression language, the need for scripting variables is significantly reduced. This is why all the JSTL tags expose information only as JSP-scoped attributes (no scripting variable is exposed). These exported JSP-scoped attributes are referred to as scoped variables in the JSTL; this helps to prevent too much overloading of the term “attribute.”