1.先写一个接口
interface ScheduleIterator.java
import java.util.Date;
public interface ScheduleIterator {
public Date next();
public Date next_time();
}
2.实现 class
DailyIterator.java
import java.util.Calendar;
import java.util.Date;
public class DailyIterator implements ScheduleIterator {
private final int hourOfDay, minute, second;
private final Calendar calendar = Calendar.getInstance();
public DailyIterator(int hourOfDay, int minute, int second) {
this(hourOfDay, minute, second, new Date());
}
public DailyIterator(int hourOfDay, int minute, int second, Date date) {
this.hourOfDay = hourOfDay;
this.minute = minute;
this.second = second;
calendar.setTime(date);
calendar.set(Calendar.HOUR_OF_DAY, hourOfDay);
calendar.set(Calendar.MINUTE, minute);
calendar.set(Calendar.SECOND, second);
calendar.set(Calendar.MILLISECOND, 0);
if (!calendar.getTime().before(date)) {
calendar.add(Calendar.DATE, -1);
}
}
//下一天,
public Date next() {
calendar.add(Calendar.DATE, 1);
return calendar.getTime();
}
//下一个分钟
public Date next_time() {
calendar.add(Calendar.MINUTE, 1);
System.out.println("===="+calendar.getTime());
return calendar.getTime();
}
//内部测试
public static void main(String[] args)
{
DailyIterator d= new DailyIterator(11,45,0);
System.out.println(d.next_time());
}
}
3.Scheduler.java 具体实现的定时任务的class
import java.util.Date;
import java.util.Timer;
import java.util.TimerTask;
public class Scheduler {
class SchedulerTimerTask extends TimerTask {
private SchedulerTask schedulerTask;
private ScheduleIterator iterator;
public SchedulerTimerTask(SchedulerTask schedulerTask,
ScheduleIterator iterator) {
this.schedulerTask = schedulerTask;
this.iterator = iterator;
}
public void run() {
schedulerTask.run();
reschedule(schedulerTask, iterator);
}
}
private final Timer timer = new Timer();
public Scheduler() {
}
public void cancel() {
timer.cancel();
}
public void schedule(SchedulerTask schedulerTask,
ScheduleIterator iterator) {
Date time = iterator.next_time();
if (time == null) {
schedulerTask.cancel();
} else {
synchronized(schedulerTask.lock) {
if (schedulerTask.state != SchedulerTask.VIRGIN) {
throw new IllegalStateException("Task already scheduled " + "or cancelled");
}
schedulerTask.state = SchedulerTask.SCHEDULED;
schedulerTask.timerTask =
new SchedulerTimerTask(schedulerTask, iterator);
timer.schedule(schedulerTask.timerTask, time);
}
}
}
private void reschedule(SchedulerTask schedulerTask,
ScheduleIterator iterator) {
Date time = iterator.next_time();
if (time == null) {
schedulerTask.cancel();
} else {
synchronized (schedulerTask.lock) {
if (schedulerTask.state != SchedulerTask.CANCELLED) {
schedulerTask.timerTask = new SchedulerTimerTask(
schedulerTask, iterator);
timer.schedule(schedulerTask.timerTask, time);
}
}
}
}
}
4.AlarmClock.java
import java.text.SimpleDateFormat;
import java.util.Date;
public class AlarmClock {
private final Scheduler scheduler = new Scheduler();
private final SimpleDateFormat dateFormat = new SimpleDateFormat(
"dd MMM yyyy HH:mm:ss.SSS");
private final int hourOfDay, minute, second;
public AlarmClock(int hourOfDay, int minute, int second) {
this.hourOfDay = hourOfDay;
this.minute = minute;
this.second = second;
}
public void start() {
scheduler.schedule(new SchedulerTask() {
public void run() {
soundAlarm();
}
private void soundAlarm() {
System.out.println("Wake up! " + "It's "
+ dateFormat.format(new Date()));
// Start a new thread to sound an alarm...
}
}, new DailyIterator(hourOfDay, minute, second));
}
public static void main(String[] args) {
//13 28 0 从某一个小时分钟秒从始,
AlarmClock alarmClock = new AlarmClock(13, 28, 0);
alarmClock.start();
}
}