You need a servlet container/Java EE -server to run the web application, for example Tomcat. It's fairly easy to setup (The Tomcat-pages have instructions for Windows and Linux/Unix), once you have your server up and running, you copy your application as a .war-file into the servers' webapps-directory, Tomcat will pick it up (when it's running), deploy it and start running the application.
You get the .war-file (check that your projects' pom.xml has the packaging set to <packaging>war</packaging>
) from your project by running mvn package (in Eclipse, click project root with the right mouse button, select Run as... -> Maven package). The .war-file will appear under the target-directory of the project.