如何阻止Callable提交给ExecutorService？ [英] How to stop a Callable submitted to ExecutorService?

问题描述

我正在尝试实现一个示例应用程序来测试 Callable 和 ExecutorService 接口。

I'm trying to implement a sample application to test Callable and ExecutorService interfaces.

在我的应用程序中，我声明：

In my app I have declared:

ExecutorService exSvc = Executors.newSingleThreadExecutor();

然后：

Future<Integer> test = exSvc.submit(
    new Callable<Integer>() {
        public Integer call() {
            for(int i = 0; i < 1000; i++){
                System.out.println(i);
            }
            return 1;
        }
    });

现在我试图在终止之前停止进程，我正在使用 exSvc.shutdownNow（）但它不起作用。

Now I'm trying to stop the process before it terminate, I'm using exSvc.shutdownNow() but it doesn't work.

优雅地停止经典的线程我通常使用某种条件变量。这是跟随 ExecutorService 的常见方法？

To stop gracefully a classical Thread I usually use some kind of condition variable. Which is a common approach to follow with ExecutorService?

推荐答案

Future.cancel（true）和 ExecutorService.shutdownNow（）使用线程中断。只要您不在任务中进行不间断的阻塞调用，您只需要正确处理中断条件，如下所示：

Future.cancel(true) and ExecutorService.shutdownNow() use thread interruption. As long as you don't make uninterruptable blocking calls in your task, all you need is to handle interrupted condition correctly, something like this:

for(int i = 0; i < 1000; i++){
    // Uses isInterrupted() to keep interrupted status set
    if (Thread.currentThread().isInterrupted()) {
        // Cannot use InterruptedException since it's checked
        throw new RuntimeException(); 
    }
    System.out.println(i);
}

如果您进行不间断的阻止呼叫（例如网络IO），事情会变得更多复杂的，您需要以某种方式手动中断它们，例如，通过关闭底层套接字。

If you make uninterruptable blocking calls (such as network IO), things become more complex, you need to interrupt them manually somehow, for example, by closing the underlying sockets.

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