Head First Servlets and JSP, 2nd Edition

But wait... there’s still another JSP element we haven’t seen: actions

So far, you’ve seen five different types of elements that can appear in a JSP: scriptlets, directives, declarations, Java expressions, and EL expressions.

But we haven’t seen actions. They come in two flavors: standard and...not.

Standard Action:

<jsp:include page="wickedFooter.jsp" />

Note

For now, don’t worry about what these do or how they work, just recognize an action when you see the syntax in a JSP. Later, we’ll go into the details.

Other Action:

<c:set var="rate" value="32" />

Although that’s misleading, because there are some actions that aren’t considered standard actions, but which are still part of a now-standard library. In other words, you’ll later learn that some of the non-standard (the objectives refer to them as custom) actions are... standard, but yet they still aren’t considered “standard actions”. Yes, that’s right—they’re standardized non-standard custom actions. Doesn’t that just clear it right up for you?

In a later chapter when we get to “using tags”, we’ll have a slightly richer vocabulary with which to talk about this in more detail, so relax. For now, all we care about is recognizing an action when you see it in a JSP!

Sharpen your pencil

Look at the syntax for an action, and compare it to the syntax for the other kinds of JSP elements. Then answer this:

1. What are the differences between an action element and a scriptlet?

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2. How will ...