JUC-线程池调度-ScheduledThreadPool

线程调度使用类：ScheduledExecutorService

创建线程池调度类对象：

ScheduledExecutorService pool = Executors.newScheduledThreadPool(5);

向线程池中添加任务的方法不是submit，而是：schedule

    public <V> ScheduledFuture<V> schedule(Callable<V> callable, long delay, TimeUnit unit);

包含3个参数：

callable：线程执行的任务

delay：要延迟的时间

unit：延迟时间的单位：例如：秒：TimeUnit.SECONDS，分：TimeUnit.MINUTES。

例子：使得线程池中每个线程没隔3秒执行一次：

package com.atguigu.juc;

import java.util.Random;
import java.util.concurrent.Callable;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

public class TestScheduledThreadPool {

    public static void main(String[] args) throws Exception {
        ScheduledExecutorService pool = Executors.newScheduledThreadPool(5);

        for (int i = 0; i < 5; i++) {
            Future<Integer> result = pool.schedule(new Callable<Integer>(){

                @Override
                public Integer call() throws Exception {
                    int num = new Random().nextInt(100);//生成随机数
                    System.out.println(Thread.currentThread().getName() + " : " + num);
                    return num;
                }

            }, , TimeUnit.SECONDS);

            System.out.println(result.get());
        }
        pool.shutdown();
    }
}

执行结果：

pool-1-thread-1 : 57
57
pool-1-thread-1 : 55
55
pool-1-thread-2 : 45
45
pool-1-thread-1 : 50
50
pool-1-thread-3 : 88
88