Many of us build war files as part of the project, however some projects stilll use jar and copy ant tasks to assemble war file. However ant has a built-in war task which takes care of web.xml, classes, libraries etc.,
Here is sample of ant war task.
<war destfile=”myapp.war” webxml=”myapp/web.xml”>
<classes dir=”myapp/classes” />
<exclude name=”whatever you need to exclude” />
<fileset dir=”myapp/jsp” />
<fileset dir=”myapp/html” />