How to return 404 with Spring WebFlux

Question

I\'m having a controller like this one (in Kotlin):

@RestController
@RequestMapping(\"/\")
class CustomerController (private val service: CustomerService) {
             


        

Answer 1

Instead of throwing an exception the method's implementation can be changed to

fun findById(@PathVariable id: String,
             @RequestHeader(value = IF_NONE_MATCH) versionHeader: String?): Mono> =
    return service.findById(id)
        .map {
            // ETag stuff ...
            ok().eTag("...").body(...)
        }
        .defaultIfEmpty(notFound().build())