Maybe you should try Bristleback Server? Using Bristleback, you may choose from several WebSockets engines, like Jetty, Netty and Tomcat. You can have standalone server as well as web application that uses WebSockets (Jetty and Tomcat 7). Bristleback uses Spring Framework. If you have worked with web frameworks like Struts, Stripes or Play!, it will be very easy for you to start. Of course, Bristleback has its own JavaScript client library for even easier development.
Full disclosure: I am one of the co-creators of Bristleback Server.
