How to validate a model model in web flux SpringBoot - spring-boot

Question

I'm trying to move from traditional approach to Reactive style. Early days for me. One of the challenge I came into and could not make much progress is on model validation. With RestControllers, it was as easy as #Valid.
I don't see anything out there to make it happen for Webflux way of doing things
package com.reactive.sbhello.handler;
import com.reactive.sbhello.model.Order;
import com.reactive.sbhello.service.OrderService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.MediaType;
import org.springframework.stereotype.Component;
import org.springframework.web.reactive.function.BodyInserters;
import org.springframework.web.reactive.function.server.ServerRequest;
import org.springframework.web.reactive.function.server.ServerResponse;
import reactor.core.publisher.Mono;
import javax.validation.Validator;
#Component
public class OrderHandler {
#Autowired
private OrderService orderService;
private final Validator validator;
public OrderHandler(Validator validator) {
this.validator = validator;
}
public Mono<ServerResponse> getAll(ServerRequest request) {
return ServerResponse.ok()
.contentType(MediaType.APPLICATION_JSON)
.body(orderService.getAllOrders(),
Order.class
);
}
public Mono<ServerResponse> getOrderInfo(ServerRequest request) {
var orderId = request.pathVariable("orderId");
var response = orderService.getOrderById(Integer.parseInt(orderId));
return response.collectList()
.flatMap(orders -> {
if(orders.isEmpty()) {
return ServerResponse.badRequest().body(BodyInserters.fromValue("Invalid OrderId"));
} else {
return ServerResponse.ok().body(BodyInserters.fromValue(orders));
}
});
}
public Mono<ServerResponse> addOrder(ServerRequest request) {
return request.bodyToMono(Order.class)
.flatMap(order -> orderService.addOrder(order))
.flatMap(order -> ServerResponse.ok()
.contentType(MediaType.APPLICATION_JSON)
.body(BodyInserters.fromValue(order)));
}
}
"addOrder" function at the moment lacks any validation. As a result, null values go through. Is there anyway to validate apart from doing it in service and bubble up the error? Or should I stick to RestController approach and still use streaming from there.