Using a tag library in a JSP

Besides the six standard tags, in a JavaServer page we can also use tags from a tag library.
The Apache Software Foundation has developed a number of tag libraries: this is the jakarta-taglibs project.
Of interest to us is a tag library containing tags for processing XML input and applying XSL transformations.

Here is a JavaServer page that uses these tags:

<%@page language="java" %>
<%@taglib uri="http://jakarta.apache.org/taglibs/xsl-1.0"
          prefix="xsltlib" %>
<html>
<head>
<title>Consumables example</title>
</head>
<body>
<xsltlib:apply xml="/xml.processing/consumables.xml" 
               xsl="/xml.processing/consumables.xsl" />
</body>
</html>

The above text is in the file http://www.dur.ac.uk/barry.cornelius/java/xml.processing/code/Consumables.jsp.
It can be executed by going to: http://altair.dur.ac.uk:8080/barry.cornelius/xml.processing/jsp/Consumables.jsp.
Three files are needed to get this to work with tomcat:
- web.xml is used to associate http://jakarta.apache.org/taglibs/xsl-1.0 with the location of xsl.tld.
- xsl.tld contains a definition of the tag library together with names of the Java classes that implement the tags.
- xsl.jar contains the .class files of these classes.