JUC(十二)-线程中断相关问题(LockSupport,sleep,InterruptException)

JUC线程中断相关问题总结

一、 sleep 和线程中断之间的关系和特点

结论

1. 线程调用 Thread.sleep之后会进入休眠状态 , 当前线程被中断后(其他线程调用了当前线程的interrupt()方法) , 那么就会抛出异常 需要捕获sleep的异常 , 这个正在休眠的线程会被迫唤醒

2. 休眠的线程被中断后 唤醒后 其中断标记位会重置为false （可通过 thread.isInterrupted() 方法来验证）

测试验证代码如下

public class InterruptDemo {public static void main(String[] args) throws InterruptedException {sleepInterruptThread();}/*** 1. 中断调用了sleep方法的进行休眠的线程** 输出结果：** 1.SleepInterruptThread|| false* ERROR==>抛出异常:sleep interrupted* 2.SleepInterruptThread|| false* 3.1683772273061|| false* 4.1683772275072|| 完成任务！** 结论：*  线程调用sleep后 被中断是会抛出InterruptException , 并且线程的中断标记位会重置为false*  因此再次休眠 不会抛出中断异常!**/private static void sleepInterruptThread() throws InterruptedException {Thread t1 = new Thread(() -> {System.out.println("1." + Thread.currentThread().getName() + "|| " + Thread.currentThread().isInterrupted());try {Thread.sleep(10000);} catch (InterruptedException e) {System.out.println("ERROR==>抛出异常:" + e.getMessage());System.out.println("2." + Thread.currentThread().getName() + "|| " + Thread.currentThread().isInterrupted());}System.out.println("3." + System.currentTimeMillis() + "|| " + Thread.currentThread().isInterrupted());try {Thread.sleep(2000);} catch (InterruptedException e) {e.printStackTrace();}System.out.println("4." + System.currentTimeMillis() + "|| 完成任务！");},"SleepInterruptThread");t1.start();Thread.sleep(1000);t1.interrupt();}}

二、 LockSupport 和线程中断之间的关系

结论

1. 被LockSupport.park 挂起的线程 在被中断后 也会被唤醒 但是和sleep的区别是 这个方法并不会抛出InterruptException异常

2. 中断唤醒之后不会抛出异常 ， 但是这个线程的中断标记位变为了true 并不会重置 （可通过 thread.isInterrupted() 方法来验证）

测试验证代码如下

测试LockSupport.park中断后的线程状态 , 还有中断后和sleep方法结合使用

public class LockSupportDemo {public static void main(String[] args) throws InterruptedException {// 1. 测试LockSupport挂起的线程 被中断是否抛出异常lockSupport();Thread.sleep(1000);System.out.println("=============================================");System.out.println("=============================================");System.out.println("=============================================");// 2. 测试LockSupport中断后和sleep方法一起使用lockSupportSleep();}/*** 1. 被LockSupport.park 挂起的线程 调用中断方法后并不会抛出异常 , 但是线程的中断标记位的确变为了true** 输出结果:** 1.LockSupportThread||false* 3.LockSupportThread||true* 2.LockSupportThread||true** 可以看到通过 LockSupport 挂起的线程在被中断后并不会抛出异常 但是中断标记位是改为了true**/private static void lockSupport() throws InterruptedException {Thread t1 = new Thread(() -> {System.out.println("1." + Thread.currentThread().getName() + "||" + Thread.currentThread().isInterrupted());// 将线程挂起LockSupport.park();System.out.println("2." + Thread.currentThread().getName() + "||" + Thread.currentThread().isInterrupted());// 如果后边跟上 Thread.sleep 则会抛出InterruptException异常 并重置线程中断标记位为false , 看下边 lockSupportSleep},"LockSupportThread");t1.start();Thread.sleep(500);t1.interrupt();System.out.println("3." + t1.getName() + "||" + t1.isInterrupted());}/*** 2. LockSupport中断线程后 和sleep方法结合使用** 输出结果:** 1.LockSupportSleepThread||false* 2.LockSupportSleepThread||true* 抛出异常==》sleep interrupted* 3.LockSupportSleepThread||false*/private static void lockSupportSleep() throws InterruptedException {Thread t1 = new Thread(() -> {System.out.println("1." + Thread.currentThread().getName() + "||" + Thread.currentThread().isInterrupted());// 将线程挂起LockSupport.park();System.out.println("2." + Thread.currentThread().getName() + "||" + Thread.currentThread().isInterrupted());// 如果后边跟上 Thread.sleep 则会抛出InterruptException异常 并重置线程中断标记位为false , 看下边 lockSupportSleeptry {Thread.sleep(1000);} catch (InterruptedException e) {System.out.println("抛出异常==》" + e.getMessage());System.out.println("3." + Thread.currentThread().getName() + "||" + Thread.currentThread().isInterrupted());}},"LockSupportSleepThread");t1.start();Thread.sleep(500);t1.interrupt();}}