CompletableFuture-通用异步编程

演示Completable接口完全可以代替Future接口：

CompletableFuture减少阻塞和轮询，可以传入回调对象，当异步任务完成或者发生异常时，自动

调用回调对象的回调方法。

package com.nanjing.gulimall.zhouyimo.test;

import java.util.concurrent.*;

/**
 * @author zhou
 */
public class CompletableFutureUseDemo {
    public static void main(String[] args) throws ExecutionException, InterruptedException {
        ExecutorService executorService = Executors.newFixedThreadPool(3);
        CompletableFuture completableFuture = CompletableFuture.supplyAsync(() -> {
            System.out.println(Thread.currentThread().getName() + "---come in");
            int result = ThreadLocalRandom.current().nextInt(10);
            try {
                TimeUnit.SECONDS.sleep(1);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            if (result > 5) { //模拟产生异常情况
                int i = 10 / 0;
            }
            System.out.println("----------1秒钟后出结果" + result);
            return result;
        }, executorService).whenComplete((v, e) -> {
            if (e == null) {
                System.out.println("计算完成，更新系统" + v);
            }
        }).exceptionally(e -> {
            e.printStackTrace();
            System.out.println("异常情况：" + e.getCause() + " " + e.getMessage());
            return null;
        });
        System.out.println(Thread.currentThread().getName() + "先去完成其他任务");
        executorService.shutdown();
    }
}

改下随机数测试正确的情况：