Identifying a JSP Document

The container needs help to recognize a JSP page as a page using the XML syntax. A JSP 2.0 container follows these rules, in this order:

  • The requested page has an extension matching the URL pattern of a JSP group declaration in the web.xml file with <is-xml> set to true, as described earlier.

  • The requested page has the .jspx extension, unless this extension has been disabled by a JSP group with <is-xml> set to false. For a tag file in XML syntax, the .tagx extension must be used.

  • The requested page is identified as a JSP page (through the default .jsp extension or an extension defined by a JSP group declaration) and its root element is <jsp:root>.

The third rule was the only one supported by JSP 1.2, as I mentioned earlier, and it’s primarily kept for backward compatibility. For new applications, you probably want to rely on one of the first two rules instead.

Let’s use a simple JSP Document to discuss the syntax requirements in more detail. Example 17-10 shows a JSP Document that illustrates most of the things you need to consider, as well as the main features available for this format.

Example 17-10. A JSP Document (jspdocument.jspx)
                     <html xmlns="http://www.w3c.org/1999/xhtml" xmlns:jsp="http://java.sun.com/JSP/Page" xml:lang="en" lang="en"> <jsp:output doctype-root-element="html" doctype-public="-//W3C//DTD XHTML 1.0 Transitional//EN" doctype-system="http://www.w3c.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"/> <jsp:directive.page contentType="text/html" /> ...

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