问如何使用JDK的HttpClient获取我订阅的响应的状态代码？

EN

// a subscriber which expresses a complete lack of interest in the body
private static class Unsubscriber implements HttpResponse.BodySubscriber<Void> {
    @Override
    public CompletionStage<Void> getBody() {
        return CompletableFuture.completedStage(null);
    }

    @Override
    public void onSubscribe(Flow.Subscription subscription) {
        subscription.cancel();
    }

    @Override
    public void onNext(List<ByteBuffer> item) {}

    @Override
    public void onError(Throwable throwable) {}

    @Override
    public void onComplete() {}
}


// wraps another handler, and only uses it for an expected status
private static HttpResponse.BodyHandler<Void> expectingStatus(int expected, HttpResponse.BodyHandler<Void> handler) {
    return responseInfo -> responseInfo.statusCode() == expected ? handler.apply(responseInfo) : new Unsubscriber();
}

// used like this
Flow.Subscriber<String> subscriber = createSubscriberSomehow();
HttpResponse<Void> response = HttpClient.newHttpClient()
                                        .send(HttpRequest.newBuilder()
                                                         .uri(URI.create("http://example.org/api"))
                                                         .build(),
                                              expectingStatus(200, HttpResponse.BodyHandlers.fromLineSubscriber(subscriber)));