固定线程池立即退出，不处理线程

Question

试图理解固定线程池我做了这个测试代码，它显示了以下结果，与我认为它会做的相反：

Thread Start: 1

Thread Start: 2

Thread Start: 0

就是这样。没有“线程结束”消息，仅启动了 3 个线程。

我期望并且我希望完成所有 10 个任务。

ExecutorService exec = Executors.newFixedThreadPool(3);

for (int c = 0; c < 10; c++) {

    exec.execute(new TestThread(c));

}

exec.shutdown();

public class TestThread implements Runnable {

    private int counter;

    public TestThread (int counter) {

        this.counter = counter;

    }

    @Override

    public void run() {

        System.out.println("Thread Start: " + counter);

        try {

            Thread.sleep(1000);

        } catch (InterruptedException e) {

            e.printStackTrace();

        }

        System.out.println("Thread End: " + counter);

    }

}

Answer 1

exec.shutdown()不阻塞主线程。如果您需要等待所有提交的任务完成，您需要exec.awaitTermination(1, TimeUnit.HOUR);在调用exec.shutdown();./**&nbsp;* Blocks until all tasks have completed execution after a shutdown&nbsp;* request, or the timeout occurs, or the current thread is&nbsp;* interrupted, whichever happens first.&nbsp;*/boolean awaitTermination(long timeout, TimeUnit unit)&nbsp; &nbsp; throws InterruptedException;