DispatcherServlet in Springboot is not working

Question

In Springboot 3.0 We have registered a servlet ss000Action that extends from HttpServlet and does nothing inside. Use ServletRegistrationBean to register ss000Action servlet with

addUrlMappings("/sp/*")
setLoadOnStartup(1)

Create ss0001Filter Use ServletRegistrationBean to register ss000Action servlet into ss0001Filter used to remove /sp on url.

setFilter(ss0001Filter)
addServletRegistrationBeans(ss000Action ())

When submitting a url:

/sp/ss2000 => ss0001Filter => /ss2000 => ss2000 Controller processing => forward :/sp/ss1000

In the controller I have registered:

@RequestMapping(value = "/sp/ss1000"

However, a white screen error is occurring.

Please help me explain why this is so.

Is it because I registered a servlet that overrides the Dispatcher Servlet?

Is there any documentation that explains this?

What to do to solve it?