java定时器（每天定时执行 每月某天执行）

每天定时执行（方法1）

public class DayInterval implements ServletContextListener{
	public static void showDayTime() {
		Date sendDate = new Date();
		Timer dTimer = new Timer();
		dTimer.schedule(new TimerTask() {
			@Override
			public void run() {
				Calendar c = Calendar.getInstance();
				int hour = c.get(Calendar.HOUR_OF_DAY);
				int minutes = c.get(Calendar.MINUTE);
				if (hour == 11 && minutes == 38) {
					// 每天执行，若为11:38
					System.out.println("每日任务已执行");
				}
			}
		}, sendDate, 24* 60* 60 * 1000);//设置24小时执行一次
	}
	
	public static void main(String[] args) {
		showDayTime();
	}

	@Override
	public void contextDestroyed(ServletContextEvent arg0) {
		// TODO Auto-generated method stub
		
	}

	@Override
	public void contextInitialized(ServletContextEvent arg0) {
		showDayTime();
		
	}

每天定时执行（方法2）

public static void showDayTime() {
            Calendar calendar = Calendar.getInstance();
		int year = calendar.get(Calendar.YEAR);
		int month = calendar.get(Calendar.MONTH);
		int day = calendar.get(Calendar.DAY_OF_MONTH);

		calendar.set(year, month, day, 10, 44, 00);//设置要执行的日期时间

		Date defaultdate = calendar.getTime();

		Timer dTimer = new Timer();
		dTimer.schedule(new TimerTask() {
		@Override
		public void run() {	
		     System.out.println("每日任务已经执行");
		}
		}, defaultdate , 24* 60* 60 * 1000);//24* 60* 60 * 1000
	}
	
	public static void main(String[] args) {
		showDayTime();
	}

每月定时执行

public static void showMonthTime() {
		Date sendDate = new Date();
		
		Timer dTimer = new Timer();
		dTimer.schedule(new TimerTask() {
			@Override
			public void run() {
				Calendar c = Calendar.getInstance();
				int day = c.get(Calendar.DAY_OF_MONTH);
				if (day == 30) {
					// 每天执行，若为每月30号才执行
					System.out.println("每月定时任务已执行");
				}
			}
		}, sendDate,  24* 60* 60 * 1000);//24* 60* 60 * 1000
	}
	
	public static void main(String[] args) {
		showMonthTime();
	}