JUC并发编程 共享模式之工具 ThreadPoolExecutor -- 线程池应用之定时任务（在每周周四执行定时任务）

Posted 2021-10-21 Z && Y

1. 线程池应用之定时任务

示例: 在每周周四执行定时任务

package com.tian;

import java.time.DayOfWeek;
import java.time.Duration;
import java.time.LocalDateTime;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

public class TestSchedule {
    private static LocalDateTime nowTime;

    // 如何让每周四 18:00:00 定时执行任务？
    public static void main(String[] args) {
        LocalDateTime nextThursdayTime = getTheTimeOfNextThursday();
        // initailDelay 代表当前时间和周四的时间差
        // period 一周的间隔时间
        long initailDelay = Duration.between(nowTime, nextThursdayTime).toMillis();
        long period = 1000 * 60 * 60 * 24 * 7;
        ScheduledExecutorService pool = Executors.newScheduledThreadPool(1);
        pool.scheduleAtFixedRate(() -> {
            System.out.println("running...");
        }, initailDelay, period, TimeUnit.MILLISECONDS);
    }

    /**
     * 获取下周周四时间
     */
    public static LocalDateTime getTheTimeOfNextThursday() {
        //  获取当前时间
        nowTime = LocalDateTime.now();
        // 获取周四时间
        LocalDateTime time = nowTime.withHour(18).withMinute(0).withSecond(0).withNano(0).with(DayOfWeek.THURSDAY);
        // 如果 当前时间 > 本周周四
        if (nowTime.compareTo(time) > 0) {
            // time 加 1周, 为下周周四
            time = time.plusWeeks(1);
        }
        return time;
    }
}

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