ExecutorService取代Timer(补足六个汉字).docVIP

《Java并发编程实战》一书提到的用ExecutorService取代Java Timer有几个理由，我认为其中最重要的理由是： 如果TimerTask抛出未检查的异常，Timer将会产生无法预料的行为。Timer线程并不捕获异常，所以 TimerTask抛出的未检查的异常会终止timer线程。这种情况下，Timer也不会再重新恢复线程的执行了;它错误的认为整个Timer都被取消了。此时，已经被安排但尚未执行的TimerTask永远不会再执行了，新的任务也不能被调度了。 stackoverflow上也有关于此问题的讨论： HYPERLINK /questions/409932/java-timer-vs-executorservice/questions/409932/java-timer-vs-executorservice Timer的问题： Java代码 package com.ljn.timer; import java.util.Date; import java.util.Timer; /** * @author lijinnan * @date:2013-11-25 下午3:27:43 */ public class TimerException { public static void main(String[] args) { System.out.println(start: + new Date()); Timer timer = new Timer(); int delay = 1000; int period = 2000; timer.schedule(new OKTask(), delay * 2, period); //OKTask does not get chance to execute timer.schedule(new ErrorTask(), delay, period); //exception in ErrorTask will terminate the Timer } /*输出： start:Mon Nov 25 17:49:53 CST 2013 ErrorTask is executing... error:Mon Nov 25 17:49:55 CST 2013 Exception in thread Timer-0 java.lang.RuntimeException: something wrong at com.ljn.timer.ErrorTask.run(ErrorTask.java:14) */ } 用ExecutorService则正常： Java代码 package com.ljn.timer; import java.util.Date; import java.util.concurrent.Executors; import java.util.concurrent.ScheduledExecutorService; import java.util.concurrent.TimeUnit; /** * @author lijinnan * @date:2013-11-25 下午3:35:39 */ public class ScheduledExecutorServiceTest { public static ScheduledExecutorService scheduledExecutorService = Executors.newScheduledThreadPool(2); public static void main(String[] args){ System.out.println(start: + new Date()); ErrorTask errorTask = new ErrorTask(); OKTask okTask = new OKTask(); int delay = 1000; int period = 2000; scheduledExecutorService.scheduleAtFixedRate