There are errors in your web.xml and in your servlet. Start here and read about the types of paths and relative links to correct your web.xml. Then put your servlet in a package. Never use the default of no package.
"The good news about computers is that they do what you tell them to do. The bad news is that they do what you tell them to do." -- Ted Nelson
I’ve looked at a lot of different solutions, and in my humble opinion Aspose is the way to go. Here’s the link: http://aspose.com