JavaServer Pages, 3rd Edition

Using JSP Directive Elements

Let’s look at each piece of Example 5-1 in detail. The first two lines are JSP directive elements. Directive elements specify attributes of the page itself, such as the type of content produced by the page, page-buffering requirements, declaration of other resources used by the page, and how possible runtime errors should be handled. Hence, a directive doesn’t directly affect the content of the response sent to the browser, but it tells the container how it should handle the page. There are three different directives that you can use in a JSP page: page, include, and taglib. In this chapter, we’re using the page and the taglib directives. The include directive is described in Chapter 17.

JSP pages typically starts with a page directive that specifies the content type for the page:

<%@ page contentType="text/html" %>

A JSP directive element starts with a directive-start identifier (<%@ ), followed by the directive name (page in this case), directive attributes, and ends with %>. A directive contains one or more attribute name/value pairs (e.g., contentType="text/html“). Note that JSP element and attribute names are case-sensitive, and in most cases, the same is true for attribute values. All attribute values must also be enclosed in single or double quotes.

The page directive has many possible attributes. In Example 5-1, only the contentType attribute is used. It specifies the MIME-type for the content the page produces. The most common values are text/html ...