Spring boot Spring WebClient错误-reactor.core.publisher.FluxOnAssembly无法转换为reactor.core.publisher.Mono类

下面是我已经实现的rest服务

@GetMapping(produces = MediaType.TEXT_EVENT_STREAM_VALUE, value = "/events")
Flux<Event> events() {
    Flux<Event> eventFlux = Flux.fromStream(Stream.generate {new Event(System.currentTimeMillis(), LocalDate.now())})
    Flux<Long> durationFlux = Flux.interval(Duration.ofSeconds(1))
    return Flux.zip(eventFlux, durationFlux)
    .map {it.t1}
}

public static void main(String[] args) {
    SpringApplication.run(ReactiveServiceApplication)
}

我得到的错误如下

 @Bean
    WebClient client() {
        return WebClient.create("http://localhost:8080")
    }

    @Bean
    CommandLineRunner demo (WebClient client) {
        return { args ->
            client.get().uri("/events")
            .accept(MediaType.TEXT_EVENT_STREAM)
            .exchange()
            .flatMap { response -> response.bodyToFlux(Event.class) }
            .subscribe { println it }
        }
    }

    public static void main(String[] args) {
        new SpringApplicationBuilder(ReactiveClientApplication)
            .properties(Collections.singletonMap("server.port","8081"))
            .run(args)
    }

reactor.core.Exceptions$ErrorCallbackNotImplemented: java.lang.ClassCastException: class reactor.core.publisher.FluxOnAssembly cannot be cast to class reactor.core.publisher.Mono (reactor.core.publisher.FluxOnAssembly and reactor.core.publisher.Mono are in unnamed module of loader 'app')
Caused by: java.lang.ClassCastException: class reactor.core.publisher.FluxOnAssembly cannot be cast to class reactor.core.publisher.Mono (reactor.core.publisher.FluxOnAssembly and reactor.core.publisher.Mono are in unnamed module of loader 'app')
    at reactor.core.publisher.MonoFlatMap$FlatMapMain.onNext(MonoFlatMap.java:118) ~[reactor-core-3.3.5.RELEASE.jar:3.3.5.RELEASE]

---

为什么会发生错误

原因是使用

flatMap

实际返回的是

Mono

。因此，闭包

{response->response.bodyToFlux（Event.class）}

实际上返回了

Flux

，而

flatMap

期望的是

Mono

更改为

flatMapMany

将解决此问题。代码如下

    CommandLineRunner getFluxDemoExchange (WebClient client) {
        return { args ->
            client.get().uri("/events")
                    .accept(MediaType.TEXT_EVENT_STREAM)
                    .exchange()
                    .flatMapMany { response -> response.bodyToFlux(Event.class) }
                    .subscribe { println it }
        }
    }