java定时任务

import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

/**
 * 每天凌晨3点执行一次定时任务
 * @author yang
 */
public class ScheduledTest {
	
	public static void main(String[] args) {
		
		long oneDay = 24 * 60 * 60 * 1000;
		long initDelay = getTimeMillis("03:00:00") - System.currentTimeMillis();
		initDelay = initDelay > 0 ? initDelay : oneDay + initDelay;
		
		Runnable runnable = new Runnable() {
			
			@Override
			public void run() {
				System.out.println("这里是需要执行的业务逻辑");
			}
		};
		
		ScheduledExecutorService service = Executors.newSingleThreadScheduledExecutor();
		service.scheduleAtFixedRate(runnable, initDelay, oneDay, TimeUnit.MILLISECONDS);
	}
	
	
	/**
	* 获取指定时间对应的毫秒数
	* @param time "HH:mm:ss"
	* @return
	*/
	private static long getTimeMillis(String time) {
		try {
			DateFormat dateFormat = new SimpleDateFormat("yy-MM-dd HH:mm:ss");
			DateFormat dayFormat = new SimpleDateFormat("yy-MM-dd");
			Date curDate = dateFormat.parse(dayFormat.format(new Date()) + " " + time);
			return curDate.getTime();
		} catch (ParseException e) {
			e.printStackTrace();
		}
	return 0;
	}
}