This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
Search for "initialization servlet" on the manual page. This doesn't show exactly what you want. But you could configure anything you want this way. You could even write out a property file at runtime based completely on information in your web.xml.
Why do you want to though? A property file is more external/easier to change than the web.xml which is part of the app.