WebLogic: The Definitive Guide

Servlets and JSPs

WebLogic supports HTTP servlets as defined in the Servlet 2.3 specification, as well as JSP pages and tag extensions as defined in the JSP 1.2 specification. Typically, you will use servlets alongside JSPs to build a web application. WebLogic provides a number of useful additions to standard servlet and JSP configuration. For example, you can assign custom execute queues to critical servlets, and install servlets to serve static files and act as a CGI gateway.

Configuring a Custom Execute Queue

By default, all J2EE applications (except JMS resources) share the same pool of server threads for their operation. This includes the servlets and JSPs that rely on the default execute queue configured for a particular WebLogic instance. However, WebLogic also lets you assign a custom execute queue that is dedicated to an individual servlet (or JSP). In this way, you can ensure that a dedicated pool of threads is always available for a particular servlet and that it doesn’t need to compete with other services for a free server thread. Execute queues are explained is more detail in Chapter 15.

To assign an execute queue to a servlet, you need to modify the weblogic.xml descriptor file to include a dispatch-policy element for the servlet. The value of this element should match the name of a preconfigured execute queue. Here is an example:

<servlet-descriptor> <servlet-name>FooServlet</servlet-name> <init-as-principal-name>system</init-as-principal-name> <destroy-as-principal-name>system</destroy-as-principal-name> ...