@ServletComponentScan does not register servlet components in a mock web environment about spring-boot

[snicoll]

Thanks for the report but that's the wrong issue tracker. Moving to Spring Boot.

From a quick debugging session, those filters are indeed taken into account by SpringBootMockMvcBuilderCustomizer but their urlPatterns collection is empty.

[wilkinsona]

Mixing Spring's component model and the Servlet spec's component model isn't supported. This means that your sample also doesn't work as you would like when running its main method as the url patterns are ignored there too.

If you want to use @WebFilter you should not use @Component. Instead, you should enable scanning for servlet components using @ServletComponentScan:

@ServletComponentScan
@SpringBootApplication
public class WebfilterBugApplication {

    public static void main(String[] args) {
        SpringApplication.run(WebfilterBugApplication.class, args);
    }

    @WebFilter("/not/simple")
    public static class SimpleFilterOne extends OncePerRequestFilter {

        public static boolean CALLED = false;
        @Override
        protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {
        	System.out.println("One");
            CALLED = true;
            filterChain.doFilter(request, response);
        }
    }

    @WebFilter
    public static class SimpleFilterTwo extends OncePerRequestFilter {

        public static boolean CALLED = false;
        @Override
        protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {
        	System.out.println("Two");
            CALLED = true;
            filterChain.doFilter(request, response);
        }
    }

    @WebFilter(urlPatterns = "/not/simple")
    public static class SimpleFilterThree extends OncePerRequestFilter {

        public static boolean CALLED = false;
        @Override
        protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {
        	System.out.println("Three");        	
            CALLED = true;
            filterChain.doFilter(request, response);
        }
    }

    @RestController
    @RequestMapping("/rest/simple")
    public static class SimpleController {


        @GetMapping
        public String getString() {
            return "Hello World";
        }
    }
}

This will result in the @WebFilters being found and their attributes being honored when it's started using its main method. Unfortunately, it doesn't fix the tests as I have just discovered that the registration of servlet components doesn't work in a mock web environment. It works with @SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT) but not with the default mock environment. We can use this issue to fix that.