public class TestTimer {
    public static void main(String[] args) {
        TimerTask timerTask = new TimerTask() {
            @Override
            public void run() {
                System.out.println("task  run:"+ new Date());
            }
        };
        Timer timer = new Timer();
        //安排指定的任務(wù)在指定的時(shí)間開始進(jìn)行重復(fù)的固定延遲執(zhí)行。這里是每3秒執(zhí)行一次
        timer.schedule(timerTask,10,3000);
    }
}

public class TestScheduledExecutorService {
    public static void main(String[] args) {
        ScheduledExecutorService service = Executors.newSingleThreadScheduledExecutor();
        // 參數(shù)：1、任務(wù)體 2、首次執(zhí)行的延時(shí)時(shí)間
        //      3、任務(wù)執(zhí)行間隔 4、間隔時(shí)間單位
        service.scheduleAtFixedRate(()->System.out.println("task ScheduledExecutorService "+new Date()), 0, 3, TimeUnit.SECONDS);
    }
}

import java.util.Date;
import org.springframework.scheduling.Trigger;
import org.springframework.scheduling.TriggerContext;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.scheduling.annotation.SchedulingConfigurer;
import org.springframework.scheduling.config.ScheduledTaskRegistrar;
import org.springframework.scheduling.support.CronTrigger;
import org.springframework.stereotype.Component;
import java.time.LocalDateTime;
@Component 
@EnableScheduling
public class TaskCronChange implements  SchedulingConfigurer{
    public static String cron; 
    @Override
    public void configureTasks(ScheduledTaskRegistrar taskRegistrar) {
        //項(xiàng)目部署時(shí)，會(huì)在這里執(zhí)行一次，從數(shù)據(jù)庫(kù)拿到cron表達(dá)式
        cron = timerQueryMapper.getCronTime();
       Runnable task = new Runnable() {
           @Override
           public void run() {
              //任務(wù)邏輯代碼部分.
              System.out.println("I am going:" + LocalDateTime.now());
           }
       };
       Trigger trigger = new Trigger() {
           @Override
           public Date nextExecutionTime(TriggerContext triggerContext) {
              //任務(wù)觸發(fā)，可修改任務(wù)的執(zhí)行周期.
              //每一次任務(wù)觸發(fā)，都會(huì)執(zhí)行這里的方法一次，重新獲取下一次的執(zhí)行時(shí)間        
              cron = timerQueryMapper.getCronTime();
              CronTrigger trigger = new CronTrigger(cron);
              Date nextExec = trigger.nextExecutionTime(triggerContext);
              return nextExec;
           }
       };
       taskRegistrar.addTriggerTask(task, trigger);
    }
}

@Component
@EnableScheduling
public class Test implements SchedulingConfigurer {
 
    @Override
    public void configureTasks(ScheduledTaskRegistrar scheduledTaskRegistrar) {
        //創(chuàng)建一個(gè)線程池調(diào)度器，默認(rèn)是單線程執(zhí)行
        ScheduledExecutorService executorService = Executors.newScheduledThreadPool(100);
        scheduledTaskRegistrar.setScheduler(executorService);
 
        //增加任務(wù)
        scheduledTaskRegistrar.addTriggerTask(new Task("test1"),new Trig("cronExpess1"));
        scheduledTaskRegistrar.addTriggerTask(new Task("test2"),new Trig("cronExpess2"));
        scheduledTaskRegistrar.addTriggerTask(new Task("test3"),new Trig("cronExpess2"));
    }
}
 
/**
 * 業(yè)務(wù)類
 */
class Task implements Runnable{
    String task;
    public Task(String task){
        this.task = task;
    }
 
    //具體業(yè)務(wù)
    @Override
    public void run() {
        System.out.println(task+":"+LocalDateTime.now()+","+Thread.currentThread().getName());
    }
}
 
/**
 * 調(diào)度類
 */
class Trig implements Trigger{ 
    private String cronExpress;
    public Trig(String cronExpress){
        this.cronExpress = cronExpress;
    }
 
    @Override
    public Date nextExecutionTime(TriggerContext triggerContext) {
        String cron = null;
        try {
            //每次調(diào)度時(shí)加載cron表達(dá)式
            cron = new Config().getCrons().get(cronExpress);
        } catch (IOException e) {
            e.printStackTrace();
        }
        CronTrigger cronTrigger = new CronTrigger(cron);
        return cronTrigger.nextExecutionTime(triggerContext);
    }
}
 
/**
 * 加載cron表達(dá)式
 */
class Config{
    private static Map<String,String> cronMap;
    private static long preModifyTime;
    private String cronFile = "config/application.properties";
 
    public Map<String,String> getCrons() throws IOException {
        File file = new File(cronFile);
        long nowModifyTime = file.lastModified();
        if (cronMap != null && nowModifyTime == preModifyTime){
            return cronMap;
        }else {
            cronMap = new HashMap<>();
            BufferedReader br = new BufferedReader(new FileReader(file));
            String line = null;
            while ((line = br.readLine()) != null){
                String[] s = line.split("=");
                cronMap.put(s[0].trim(),s[1].trim());
            }
            preModifyTime = nowModifyTime;
            return cronMap;
        }
    }
}

cronExpess1 = 0/5 * * * * *
cronExpess2 = 0/10 * * * * *