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: 1Thread Start: 2Thread 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();.

/**

 * Blocks until all tasks have completed execution after a shutdown

 * request, or the timeout occurs, or the current thread is

 * interrupted, whichever happens first.

 */

boolean awaitTermination(long timeout, TimeUnit unit)

    throws InterruptedException;