Small webflux application

webflux.java

// AppRouter.java
@Configuration
public class AppRouter {
    // works for a single bean
    @Bean
    public RouterFunction<ServerResponse> routes(ResouceHandler resourceHandler) {
        return RouterFunctions.route(GET("/resource/{id}").and(accept(APPLICATION_JSON)), resourceHandler::get)
            .andRoute(GET("/resource/filter/{filterQuery}").and(accept(APPLICATION_JSON)), resourceHandler::getFiltered);
    }
}

// AppHandler.java

@Component
public class BookHandler {
    private final AppService appService;
    public BookHandler(AppService appService) {
        this.appService = appService;
    }
    public Mono<ServerResponse> get(ServerRequest request) {
        String id = request.pathVariable("id");
        return ok()
                .contentType(MediaType.APPLICATION_JSON)
                .body(appService.getById(id), AppModel.class);
    }
}

// AppRepository.java
public interface AppRepository extends ReactiveCrudRepository<AppModel, String> {

  Mono<AppModel> findById(Mono<String> id);

  @Query("{ 'filter': ?0 }")
  Flux<AppModel> findByFilter(String filter);
}