rx-java - 如何使用 RxJava 间隔运算符

Question

我正在学习 RxJava 运算符，我发现下面的代码没有打印任何内容:

public static void main(String[] args) {

    Observable
    .interval(1, TimeUnit.SECONDS)
    .subscribe(new Subscriber<Long>() {
        @Override
        public void onCompleted() {
            System.out.println("onCompleted");
        }

        @Override
        public void onError(Throwable e) {
            System.out.println("onError -> " + e.getMessage());
        }

        @Override
        public void onNext(Long l) {
            System.out.println("onNext -> " + l);
        }
    });
}

作为ReactiveX，间隔

create an Observable that emits a sequence of integers spaced by a particular time interval

我是否犯了错误或忘记了什么？

Answer 1

您必须阻塞直到可观察对象被消耗:

public static void main(String[] args) throws Exception {

    CountDownLatch latch = new CountDownLatch(1);

    Observable
    .interval(1, TimeUnit.SECONDS)
    .subscribe(new Subscriber<Long>() {
        @Override
        public void onCompleted() {
            System.out.println("onCompleted");
            // make sure to complete only when observable is done
            latch.countDown();
        }

        @Override
        public void onError(Throwable e) {
            System.out.println("onError -> " + e.getMessage());
        }

        @Override
        public void onNext(Long l) {
            System.out.println("onNext -> " + l);
        }
    });

    // wait for observable to complete (never in this case...)
    latch.await();
}

例如，您可以添加 .take(10) 以查看可观察的完整内容。