关闭时可使用如下代码
public static void waitUntilTerminate(final ExecutorService executorService, final int timeout) {
try {
executorService.shutdown();
if (!executorService.awaitTermination(timeout, TimeUnit.SECONDS)) { //超时后直接关闭
executorService.shutdownNow();
}
} catch (InterruptedException e) { //awaitTermination 出现中断异常也将触发关闭
executorService.shutdownNow();
}
}
但是实际使用中，可能会出现即使使用了shutdownNow方法，还是无法终止线程的问题，那是因为你的线程无法被中断
shutdownNow方法简单理解就是给在运行的线程发一个中断信号，如果你的线程忽略这个信号，那就无法停下来
举个例子来说明这个问题
public class ShutDownUtilsTest {
private ExecutorService executorService;
@Before
public void init() {
executorService = Executors.newFixedThreadPool(1);
}
@Test
public void shutDownOKTest() {
ShutDownUtils.waitUntilTerminate(executorService, 1);
CommonUtils.sleep(1); //等待线程处理中断
Assert.assertTrue(executorService.isTerminated());
}
@Test
public void shutDownNowFailTest() {
executorService.execute(this::canNotStopThread);
ShutDownUtils.waitUntilTerminate(executorService, 0);
CommonUtils.sleep(1); //等待线程处理中断
Assert.assertFalse(executorService.isTerminated());
}
@Test
public void shutDownNowOKTest() {
executorService.execute(this::stopThread);
ShutDownUtils.waitUntilTerminate(executorService, 0);
CommonUtils.sleep(1); //等待线程处理中断
Assert.assertTrue(executorService.isTerminated());
}
private void canNotStopThread() {
for (long i = 0; i < Long.MAX_VALUE; i++) {
}
}
private void stopThread() {
for (long i = 0; i < Long.MAX_VALUE && !Thread.currentThread().isInterrupted(); i++) {
}
}
}
从上面的测试用例可以看到canNotStopThread无法被shutDownNow终止
然而stopThread可以被正常终止，因为通过Thread.currentThread().isInterrupted()在判断线程是否收到了中断信号
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。