WebLogic: The Definitive Guide

JSP Tag Libraries

JSP tag libraries provide a simple, elegant way of embedding dynamic server-side request handling into a JSP page. WebLogic Server provides a tag library with custom tags that you may use in your JSP pages; this library defines the cache, repeat, and process tags. Other tags also are supplied, though these are not discussed, as much of their functionality can now be found in more standard tag library implementations, such as the Java Standard Template Library (JSTL). WebLogic also provides a tool to automatically generate a tag library for an EJB.

WebLogic’s Tag Library

WebLogic’s tag library JAR (weblogic-tags.jar) is located in WL_HOME/server/ext. It packages the tag library descriptor, the tag handler classes, and several other support classes. In order to use these tags in your JSP pages, you need to make the library available to your web application. Copy the JAR to the /WEB-INF/lib folder under the document root of the web application, and define a taglib element in the standard web.xml deployment descriptor:

<taglib>
  <taglib-uri>/weblogic-tags</taglib-uri>
  <taglib-location>/WEB-INF/lib/weblogic-tags.jar</taglib-location>
</taglib>

Now you can import the tag library into your JSP pages as follows:

 <%@ taglib uri="/weblogic-tags" prefix="wl" %>

Let’s take a closer look at the features and capabilities of these three tags.

The cache tag

The cache tag enables you to cache the output generated within the body of the tag. Because the output is usually some ...