Web Application Deployment Descriptor

The WEB-INF/web.xml file is the Java web application deployment descriptor that contains all general configuration information for the application, in addition to the JSF-specific information in the WEB-INF/faces-config.xml file described in Appendix E. Some elements are especially important for a JSF application, namely the <context-param>, <servlet>, and <servlet-mapping> elements. See the subsections for these elements for what configurations you must and can set for a JSF-application in the WEB-INF/web.xml file.

The deployment descriptor is an XML file. Starting with Servlet 2.4 and JSP 2.0, the elements it can contain and how they must be arranged are controlled by a number of XML Schema documents. The main XML Schema document, which includes the others, is available online at http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd. This XML Schema document must be referenced in the root element of the deployment description, as shown in Example F-1.

Example F-1. Web Application Descriptor root element for Servlet 2.4/JSP 2.0
<web-app xmlns="http://java.sun.com/xml/ns/j2ee"
  xmlns:xsi="http://www.w3c.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
    http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
  version="2.4>
  ...
</web-app>

If you’re not familiar with the intricate details of XML Schema and namespace declarations, just accept the fact that you must enclose all other elements in the deployment descriptor within a <web-app> ...

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