How to migrate legacy Spring MVC Form Controllers (`AbstractFormController`) to annotation-based controllers in newer Spring versions?

I’m upgrading a legacy Java Spring MVC application.

• Current setup:

  • Java 1.8 (recently upgraded from Java 1.7)
  • Spring 3.2.18
  • Uses the old AbstractFormController, SimpleFormController, and XML-based config.

• Goal: Upgrade to at least Java 10, preferably Java 17/18, and a newer Spring version (5.x or 6.x).

• Problem: In newer Spring versions, AbstractFormController and other form controllers are removed or deprecated. Everything is now annotation-based (@Controller, @RequestMapping, etc.). For example, I currently have something like this:

public class BulkRequestController  extends SimpleFormController {

public ModelAndView processFormSubmission(HttpServletRequest request, HttpServletResponse response, Object command,BindException errors) throws Exception {
        ModelAndView mav = new ModelAndView();
        
        String operation = request.getParameter("hdnOperation");
        String mode = request.getParameter("mode");
        // My Code  
        return mav;
    }

protected ModelAndView showForm(HttpServletRequest request, HttpServletResponse response, BindException errors) throws Exception {
        final ModelAndView mav = new ModelAndView();
        String mid = request.getParameter("mid");
        
        if(CoreUtility.BULK_REQ_STRIKE.equalsIgnoreCase(mid)) {
            mav.addAllObjects(setDateValues());
            mav.setViewName(getBatchStrikeFormView());
        } else {
            throw new Exception("Un-implemented mid :" + mid);
        }
        
        return mav;
    }
 }

But in the newer Spring MVC, this whole controller pattern doesn’t exist anymore.

• Question:

  1. What’s the correct way to migrate such controllers to annotation-based Spring MVC (@Controller, @PostMapping, etc.)?
  2. Are there tools or a standard migration guide for moving from Spring 3.2.x FormControllers to Spring 5/6 annotations?
  3. Any recommended step-by-step upgrade path (Spring 3 → 4 → 5 → 6) when also upgrading Java (to 10/17)?

• Extra Notes:

  • The project is large, with many XML-based Spring beans and FormControllers.
  • I don’t want to rewrite everything at once; gradual migration advice is appreciated.