Java Timer vs ExecutorService？ [英] Java Timer vs ExecutorService?

问题描述

我有代码，我使用 java.util.timer 安排任务。我环顾四周，看到 ExecutorService 可以做同样的事情。所以这个问题，你有没有使用Timer和 ExecutorService 来安排任务，一个人使用另一个人的好处是什么？

I have code where I schedule a task using java.util.timer. I was looking around and saw ExecutorService can do the same. So this question here, have you used Timer and ExecutorService to schedule tasks, what is the benefit of one using over another?

还想检查是否有人使用了 Timer 类并遇到了 ExecutorService 解决的任何问题他们。

Also wanted to check if anyone had used the Timer class and ran into any issues which the ExecutorService solved for them.

推荐答案

根据 Java实践中的并发：

• 计时器可能对系统时钟 ScheduledThreadPoolExecutor 不是。


• 计时器只有一个执行线程，因此长时间运行的任务可以延迟其他任务。 ScheduledThreadPoolExecutor 可以配置任意数量的线程。此外，如果需要，您可以完全控制已创建的线程（通过提供 ThreadFactory ）。


• <$ c中抛出的运行时异常$ c> TimerTask 杀死一个线程，从而使 Timer 死:-( ...即计划任务不再运行。 ScheduledThreadExecutor 不仅可以捕获运行时异常，还可以根据需要处理它们（通过从 afterExecute 方法> ThreadPoolExecutor ）。抛出异常的任务将被取消，但其他任务将继续运行。

• Timer can be sensitive to changes in the system clock, ScheduledThreadPoolExecutor isn't.
• Timer has only one execution thread, so long-running task can delay other tasks. ScheduledThreadPoolExecutor can be configured with any number of threads. Furthermore, you have full control over created threads, if you want (by providing ThreadFactory).
• Runtime exceptions thrown in TimerTask kill that one thread, thus making Timer dead :-( ... i.e. scheduled tasks will not run anymore. ScheduledThreadExecutor not only catches runtime exceptions, but it lets you handle them if you want (by overriding afterExecute method from ThreadPoolExecutor). Task which threw exception will be canceled, but other tasks will continue to run.

如果您可以使用 ScheduledThreadExecutor 而不是计时器，请执行此操作。

If you can use ScheduledThreadExecutor instead of Timer, do so.

还有一件事......当Java 1.4库中没有 ScheduledThreadExecutor 时，有一个 JSR 166（ java.util.concurrent ）的后端到Java 1.2,1.3,1.4 ，其中包含 ScheduledT hreadExecutor class。

One more thing... while ScheduledThreadExecutor isn't available in Java 1.4 library, there is a Backport of JSR 166 (java.util.concurrent) to Java 1.2, 1.3, 1.4, which has the ScheduledThreadExecutor class.

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