@Configuration
public class BookRouter {

    @Bean
    public RouterFunction<ServerResponse> routeBooks(BookHandler bookHandler) {
        return RouterFunctions
            .route(RequestPredicates.GET("/books")
                    .and(RequestPredicates.accept(MediaType.APPLICATION_JSON)), bookHandler::getBooks)
            .andRoute(RequestPredicates.GET("/books/{id}")
                    .and(RequestPredicates.accept(MediaType.APPLICATION_JSON)), bookHandler::getBook);
    }
}

public class BookHandler {

    public Mono<ServerResponse> getBook(ServerRequest request) {
        return ServerResponse
                .ok()
                .hint(Jackson2CodecSupport.JSON_VIEW_HINT, MyJacksonView.class)
                .body(...)
    }
}