ScheduledExecutorService周期性的定时任务

从j2se的api文档上查看ScheduledExecutorService的方法都是推迟一段时间然后相隔一段时间之后再去执行，没有想Timer定时器一样的可以在定点时间执行的api，如果也想像Timer那样定时执行就需要对ScheduledExecutorService的方法传入参数处理一下，下面是个人使用ScheduledExecutorService做的每天凌晨3点做的定时执行任务demo

package com.liu.test;
 
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.LinkedList;
import java.util.List;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
 
public class ThreadTest {
 
    public static void main(String[] args) {
        //创建含有三个线程的计划线程池
        ScheduledExecutorService service = Executors.newScheduledThreadPool(3);
        //一天的毫秒数
        long oneDay = 24 * 60 * 60 * 1000;
        //计算初始延迟的毫秒数
       long initDelay  = getTimeMillis("3:00:00") - System.currentTimeMillis();
        initDelay = initDelay > 0 ? initDelay : initDelay + oneDay;
 
        List<String> list1 = new LinkedList<String>();
        list1.add("第一个 :");
 
        List<String> list2 = new LinkedList<String>();
        list2.add("第二个 ");
 
        List<String> list3 = new LinkedList<String>();
        list3.add("第三个 ");
 
        //执行三个任务
        ScheduledFuture future = service.scheduleAtFixedRate(new RunnableTest(list1), initDelay, oneDay, TimeUnit.MILLISECONDS);
        service.scheduleAtFixedRate(new RunnableTest(list2), initDelay, oneDay, TimeUnit.MILLISECONDS);
        service.scheduleAtFixedRate(new RunnableTest(list3), initDelay, oneDay, TimeUnit.MILLISECONDS);
 
    }
 
    private static long getTimeMillis(String time) {
        // TODO Auto-generated method stub
        SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        SimpleDateFormat dayFormat = new SimpleDateFormat("yyyy-MM-dd");
 
        try {
            long fixedTime = dateFormat.parse(dayFormat.format(new Date())+" "+time).getTime();
            return fixedTime;
        } catch (ParseException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return 0;
    }
 
}
 
package com.liu.test;
 
import java.util.List;
 
public class RunnableTest implements Runnable {
 
    private List<String> list;
 
    public RunnableTest() {
    }
 
    public RunnableTest(List<String> list){
        this.list = list;
    }
 
    @Override
    public void run() {
        // TODO Auto-generated method stub
        for(int i=0;i<10;i++){
            if(i%3 == 0){
                try {
                    Thread.sleep(3000);
                    System.out.println(list.get(0)+ "3 number +" + i);
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }
    }
 
}