使用Java9 Flow API进行Reactive Programming

import java.util.concurrent.Flow;
import java.util.concurrent.Flow.Publisher;
import java.util.concurrent.Flow.Subscriber;

public class ReactiveExample {
    public static void main(String[] args) {
        // 创建一个发布者，发布一系列的数字
        Publisher<Integer> publisher = new Publisher<>() {
            @Override
            public void subscribe(Flow.Subscriber<? super Integer> subscriber) {
                subscriber.onSubscribe(new Flow.Subscription() {
                    private final int[] numbers = {1, 2, 3, 4, 5};
                    private int index = 0;

                    @Override
                    public void request(long n) {
                        for (int i = 0; i < n && index < numbers.length; i++) {
                            subscriber.onNext(numbers[index++]);
                        }
                        if (index == numbers.length) {
                            subscriber.onComplete();
                        }
                    }

                    @Override
                    public void cancel() {
                        // 取消订阅
                    }
                });
            }
        };

        // 创建一个订阅者，订阅发布者的数据
        Subscriber<Integer> subscriber = new Subscriber<>() {
            @Override
            public void onSubscribe(Flow.Subscription subscription) {
                System.out.println("Subscribed to publisher");
                subscription.request(Long.MAX_VALUE); // 请求尽可能多的数据项
            }

            @Override
            public void onNext(Integer item) {
                System.out.println("Received: " + item);
            }

            @Override
            public void onError(Throwable throwable) {
                throwable.printStackTrace();
            }

            @Override
            public void onComplete() {
                System.out.println("Completed");
            }
        };

        // 订阅发布者
        publisher.subscribe(subscriber);
    }
}