Beginning JavaServer Pages™

Chapter 3. JSP Basics 2: Generalized Templating and Server Scripting

The previous chapter presented JSP as a server-side mechanism used in the generation of dynamic HTML responses to an incoming request. It also demonstrated how static templated data (such as a fragment or a whole page of HTML) can be included and combined as part of the output. This chapter adds another dimension, showing how JSP generalized templating can be combined with scripting code written in the Java programming language.

The ability to include Java elements in a JSP page is the center of focus in this chapter. When working with JSP 2.0 and JSTL 1.1, there is very little reason to embed raw Java programming code into a JSP page. However, the Expression Language (EL) and JSTL features presented in the previous chapter are brand-new to most commercial JSP containers (compliant to the JSP 2.0 standard). Older, existing production code will typically not be using JSTL/EL, and will very likely have embedded Java code. This body of production code will need to maintained, and perhaps migrated. In this chapter, you will learn how to deal with legacy code that makes extensive use of embedded Java code via scripting elements in JSPs.

The primary mechanism of embedding Java code into a JSP page is called scripting. Scripting is typically done through scripting elements—declarations, expressions, and scriptlets—within a JSP. These elements are covered briefly in the previous chapter. This chapter fully explores the role ...