I have a web app built with Java, Spring MVC, and JDBC. The result is a WAR file.
To run it, the user has to install Java 8 JDK and Tomcat, and deploy the WAR file to the Tomcat server.
It would be great if they could just download the one file run it as a standalone application.
That is, run "the WAR file" and just browse to http://localhost:8080/myapp
Also, on Windows it would be great it was setup as a Server (like Tomcat is when installed with the installer).
Is there any way to do this? Maybe with Spring Boot or something new like that?
Yep, Spring boot is the way to go. It allows you to build an executable Jar with all dependencies and a Tomcat (by default, can be changed) embedded. But users will still need to download a JRE to execute the Jar, and a database if it's required, but you can use en embedded database like H2, HSQLDB..., depends what is your needs.