标签：port ble 方法 text utils dev target ati with
1.Timer
package com.qhong; import java.text.SimpleDateFormat; import java.util.Date; import java.util.Timer; import java.util.TimerTask; public class Main { public static void main(String[] args) { Timer timer = new Timer(); long delay1 = 1 * 1000; long period1 = 1000; // 从现在开始 1 秒钟之后，每隔 1 秒钟执行一次 job1 timer.schedule(new TimerTest("job1" +DateUtils.format(new Date(),"yyyy-MM-dd HH:mm:ss")), delay1, period1); long delay2 = 2 * 1000; long period2 = 2000; // 从现在开始 2 秒钟之后，每隔 2 秒钟执行一次 job2 timer.schedule(new TimerTest("job2"), delay2, period2); } } class TimerTest extends TimerTask { private String jobName = ""; public TimerTest(String jobName) { super(); this.jobName = jobName; } @Override public void run() { System.out.println("execute " + jobName); } } class DateUtils { /** 时间格式(yyyy-MM-dd) */ public final static String DATE_PATTERN = "yyyy-MM-dd"; /** 时间格式(yyyy-MM-dd HH:mm:ss) */ public final static String DATE_TIME_PATTERN = "yyyy-MM-dd HH:mm:ss"; public static String format(Date date) { return format(date, DATE_PATTERN); } public static String format(Date date, String pattern) { if(date != null){ SimpleDateFormat df = new SimpleDateFormat(pattern); return df.format(date); } return null; } }
execute job12017-03-10 19:48:45 execute job2 execute job12017-03-10 19:48:45 execute job12017-03-10 19:48:45 execute job2 execute job12017-03-10 19:48:45 execute job12017-03-10 19:48:45 execute job2 execute job12017-03-10 19:48:45 execute job12017-03-10 19:48:45 execute job2 execute job12017-03-10 19:48:45 execute job12017-03-10 19:48:45
Timer 的优点在于简单易用，但由于所有任务都是由同一个线程来调度，因此所有任务都是串行执行的，同一时间只能有一个任务在执行，前一个任务的延迟或异常都将会影响到之后的任务。
ScheduledExecutor
package com.qhong; import java.util.Date; import java.text.SimpleDateFormat; import java.util.concurrent.Executors; import java.util.concurrent.ScheduledExecutorService; import java.util.concurrent.TimeUnit; public class Main { public static void main(String[] args) { ScheduledExecutorService service = Executors.newScheduledThreadPool(10); long initialDelay1 = 1; long period1 = 1; // 从现在开始1秒钟之后，每隔1秒钟执行一次job1 service.scheduleAtFixedRate( new ScheduledExecutorTest("job1"), initialDelay1, period1, TimeUnit.SECONDS); long initialDelay2 = 2; long delay2 = 2; // 从现在开始2秒钟之后，每隔2秒钟执行一次job2 service.scheduleWithFixedDelay( new ScheduledExecutorTest("job2"), initialDelay2, delay2, TimeUnit.SECONDS); } } class ScheduledExecutorTest implements Runnable { private String jobName = ""; public ScheduledExecutorTest(String jobName) { super(); this.jobName = jobName; } @Override public void run() { System.out.println("execute "+ DateUtils.format(new Date(),"yyyy-MM-dd HH:mm:ss") + jobName); } } class DateUtils { /** 时间格式(yyyy-MM-dd) */ public final static String DATE_PATTERN = "yyyy-MM-dd"; /** 时间格式(yyyy-MM-dd HH:mm:ss) */ public final static String DATE_TIME_PATTERN = "yyyy-MM-dd HH:mm:ss"; public static String format(Date date) { return format(date, DATE_PATTERN); } public static String format(Date date, String pattern) { if(date != null){ SimpleDateFormat df = new SimpleDateFormat(pattern); return df.format(date); } return null; } }
execute 2017-03-10 20:03:53job1 execute 2017-03-10 20:03:54job2 execute 2017-03-10 20:03:54job1 execute 2017-03-10 20:03:55job1 execute 2017-03-10 20:03:56job1 execute 2017-03-10 20:03:56job2 execute 2017-03-10 20:03:57job1 execute 2017-03-10 20:03:58job1 execute 2017-03-10 20:03:58job2 execute 2017-03-10 20:03:59job1 execute 2017-03-10 20:04:00job1 execute 2017-03-10 20:04:00job2 execute 2017-03-10 20:04:01job1 execute 2017-03-10 20:04:02job1 execute 2017-03-10 20:04:02job2
展示了 ScheduledExecutorService 中两种最常用的调度方法 ScheduleAtFixedRate 和 ScheduleWithFixedDelay。
ScheduleAtFixedRate 每次执行时间为上一次任务开始起向后推一个时间间隔，即每次执行时间为 :initialDelay, initialDelay+period, initialDelay+2*period, …；
ScheduleWithFixedDelay 每次执行时间为上一次任务结束起向后推一个时间间隔，即每次执行时间为：initialDelay, initialDelay+executeTime+delay, initialDelay+2*executeTime+2*delay。
由此可见，ScheduleAtFixedRate 是基于固定时间间隔进行任务调度，ScheduleWithFixedDelay 取决于每次任务执行的时间长短，是基于不固定时间间隔进行任务调度。
https://www.ibm.com/developerworks/cn/java/j-lo-taskschedule/
标签：port ble 方法 text utils dev target ati with
原文地址：http://www.cnblogs.com/hongdada/p/6532894.html
