并行神器CompletableFuture

package com.gzz;

import java.util.Random;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import lombok.extern.slf4j.Slf4j;

@Slf4j
public class CompletableFutureTest {

    static ExecutorService executor = Executors.newFixedThreadPool(10);
    static Random random = new Random();

    public static void main(String[] args) {
        long start = System.currentTimeMillis();
        CompletableFuture<Void> task1 = CompletableFuture.runAsync(() -> task(1), executor);
        CompletableFuture<Void> task2 = CompletableFuture.runAsync(() -> task(3), executor);
        CompletableFuture<Void> task3 = CompletableFuture.runAsync(() -> task(4), executor);
        CompletableFuture<Void> task4 = CompletableFuture.runAsync(() -> task(2), executor);
        CompletableFuture.allOf(task1, task2, task3, task4).thenRun(() -> {
            long end = System.currentTimeMillis();
            log.info("完成全部任务耗时{}毫秒", end - start);
            executor.shutdown();
        });

    }

    private static void task(int i) {
        log.info("开始做任务{}", i);
        long start = System.currentTimeMillis();
        try {
            TimeUnit.MILLISECONDS.sleep(random.nextInt(1000));
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        long end = System.currentTimeMillis();
        log.info("完成任务{}耗时{}毫秒", i, end - start);

    }
}