Two cases:
Your architecture is full client-side: In this case the integration is very natural. Spring MVC exposes your service as a REST (JSON/XML) and your client application with AngularJS consumes your JSON. Here the .war application (Spring MVC) must be deployed in a servlet container (e.g. Tomcat) and your client application can be deployed in the same server or in a HTTP server like Nginx or Apache.
You want to keep page generation in the server-side and only use AngularJS for some DOM manipulation so your code must be deployed in the same .war (inside the WEB-INF/ folder).
Mixing the two approaches in not always a good idea. You can try Thymeleaf to stay in server-side page generation and at the same time have templating, testability and clean View code.
