Java Enterprise in a Nutshell, Third Edition

Structure of a JSF Application

JSF applications are web applications built on the Java Servlet framework, so they follow the same general packaging scheme as any other J2EE application (see Chapter 2 for more information). The jar files for the JSF implementation must be available on the web application’s classpath (usually accomplished by putting the appropriate jar files into the WEB-INF/lib directory).

For the reference implementation, the FacesServlet must be configured in the web.xml file for the application. This servlet provides the JSF engine: it’s responsible for processing requests for JSF-based pages and returning the UI in HTML format. For our example, we’re going to treat all resources with a .faces extension as a JSF target, so we configure the FacesServlet like this:

  <servlet>
        <servlet-name>Faces Servlet</servlet-name>
        <servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
        <load-on-startup>1</load-on-startup>
    </servlet>
 
    <!-- Faces Servlet Mapping -->
    <servlet-mapping>
        <servlet-name>Faces Servlet</servlet-name>
        <url-pattern>*.faces</url-pattern>
    </servlet-mapping>

Mapping *.faces to the FacesServlet instructs the servlet container to delegate all requests ending with .faces to the JSF engine.

JSF Lifecycle

So what happens when a request is sent to the JSF engine? In short, the JSF engine creates a tree containing a set of “components,” each corresponding to an element of the user interface for the page being submitted, and ensures that the correct user values are ...