Scripting in JSP Pages

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Scripting in JSP Pages

JSP scripting elements allow you to use Java programming language statements in your JSP
pages. Scripting elements are typically used to create and access objects, define methods, and
manage the flow of control. Many tasks that require the use of scripts can be eliminated by using
custom tag libraries, in particular the JSP Standard Tag Library. Because one of the goals of JSP
technology is to separate static data from the code needed to dynamically generate content, very
sparing use of JSP scripting is recommended. Nevertheless, there may be some circumstances
that require its use.

There are three ways to create and use objects in scripting elements:

Instance and class variables of the JSP page's servlet class are created in declarations and
accessed in scriptlets and expressions.

Local variables of the JSP page's servlet class are created and used in scriptlets and
expressions.

Attributes of scope objects (see

"Using Scope Objects" on page 105

) are created and used in

scriptlets and expressions.

This chapter briefly describes the syntax and usage of JSP scripting elements.

The Example JSP Pages

This chapter illustrates JSP scripting elements using webclient, a version of the hello1
example introduced in

Chapter 3, "Getting Started with Web Applications"

that accesses a web