中断执行程序线程池中的可运行对象

Question

Suppose I started 10 threads using executor framework in java. I want to stop/interrupt a callables based on certain conditions later on. What is the best way to do that. I understand future.cancel(true), does not solve the issue.

Answer 1

Check this article.

Calling shutdownNow() or cancel() doesn't stop the ongoing runnable. What these methods do is simply call .interrupt() on the respective thread(s). The problem is, your runnable doesn't handle InterruptedException (and it can't). It's a pretty common problem described in multiple books and articles, but still it's a bit counterintuitive.

In order to do that, you need to do quite a few things.

• Extend Runnable
• Make the “cancellable” resources (eg the input stream) an instance field, which provide a cancel method to your extended runnable, where you get the “cancellable” resource and cancel it (eg call inputStream.close())
• Implement a custom ThreadFactory that in turn creates custom Thread instances that override the interrupt() method and invoke the cancel() method on your extended Runnable
• Instantiate the executor with the custom thread factory (static factory methods take it as an argument)
• Handle abrupt closing/stopping/disconnecting of your blocking resources, in the run()method