You don’t need Spring Boot to create a rest controller.
Please follow the spring framework documentation on how to setup MVC
https://docs.spring.io/spring/docs/current/spring-framework-reference/web.html#spring-web
The MVC setup (the DispatcherServlet) depends on your spring version, you can either use xml or you can setup programmatically:
https://docs.spring.io/spring/docs/current/spring-framework-reference/web.html#mvc-servlet
Once this is setup, you can add a rest controller to your application. Note that a rest controller (the @RestController annotation) is a stereotype annotation that combines @ResponseBody and @Controller, in other words the Controller returns an object in the response body instead of returning a view.
This is a perfect example explaining what I said above:
http://www.programming-free.com/2014/01/spring-mvc-40-restful-web-services.html