To convert an existing Struts application to use JSF within a Struts application, you will need to perform the following steps:
Add the struts-faces.jar file to your application's WEB-INF/lib directory.
Add the JARs for your particular JSF implementation to your application's WEB-INF/lib directory.
Configure the Web Application Deployment Descriptor (web.xml) to use the Faces Front Controller.
You can now modify your application's pages to use the JSF tag libraries.