java - 无法从并发 CompletionService 获取结果

Question

我对 Java 并发包非常陌生。我使用 java.util.concurrent.CompletionService 类从池中获取结果，而无需等待其他线程完成任务。但即使执行了 10 分钟的代码，我也无法获取任务。我只是在任务中打印线程名称。这是我的代码。

public class CompletionService {

    public void execute(ThreadPoolExecutor argThreadPoolExecutor)
            throws InterruptedException, ExecutionException {
        java.util.concurrent.CompletionService<String> completionService = 
                 new ExecutorCompletionService<String>(argThreadPoolExecutor);
        int counter = 0;
        for (int i = 0; i < 4; i++) {
            Task task = new Task();
            completionService.submit(task);
            ++counter;
        }
        print(counter, completionService);
    }

    private void print(int argCounter,
            java.util.concurrent.CompletionService<String> argCompletionService)
            throws InterruptedException, ExecutionException {
        String s = argCompletionService.take().get();
        if (s != null && !s.isEmpty()) {
            System.out.println(s);
        }
    }

    public static void main(String[] args) throws InterruptedException,
            ExecutionException {
        ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(8, 8,
                3000, TimeUnit.SECONDS, new LinkedBlockingQueue<Runnable>());
        CompletionService completionService = new CompletionService();
        completionService.execute(threadPoolExecutor);
        threadPoolExecutor.awaitTermination(Long.MAX_VALUE, TimeUnit.SECONDS);
    }
}

任务类别:

public class Task implements Callable<String> {

@Override

    public String call() throws Exception {
        String name = Thread.currentThread().getName();
        return name;
    }
}

结果:pool-1-thread-1

我只得到一个线程信息。我等了 10-15 分钟仍然没有得到结果。我有什么地方说错了吗？谁可以帮我这个事。？

感谢。

Answer 1

completionService.execute(threadPoolExecutor);
threadPoolExecutor.awaitTermination(Long.MAX_VALUE, TimeUnit.SECONDS);

你将永远阻塞在这里，因为你没有向ThreadPoolExecutor请求shutdown .