This is the example project referred to in the Struts 2 documentation, Processing Forms tutorial. See: http://struts.apache.org.
To build the application's war file run mvn clean package from the project's root folder.
The war file is created in the target sub-folder.
Copy the war file to your Servlet container (e.g. Tomcat, GlassFish) and then startup the Servlet container.
In a web browser go to: http://localhost:8080/Form_Processing_Struts2_Mvn/index.action.
You should see a web page with Welcome to Struts 2!