多线程基础

多线程基础

文章目录

• 一、打断的三个方法
• 二、代码示例
• 三、什么方法被打断会抛出InterruptedException
• 四、能否打断BLOCK状态
• 五、能否打断Lock.lock()

一、打断的三个方法

• boolean isInterrupted();

获取线程是否被打断

• void interrupt();

打断线程

• static boolean interrupted();

获取线程是否被打断，如果被打断，复位。

二、代码示例

1.3个方法使用示例：

public static void main(String[] args) {Thread t1 = new Thread(() -> {System.out.println("初始状态："+Thread.currentThread().isInterrupted());while(true) {if(Thread.currentThread().isInterrupted()) {System.out.println("被打断状态："+Thread.currentThread().isInterrupted());// 复位boolean interrupted = Thread.interrupted();System.out.println("复位返回值："+interrupted);System.out.println("复位后状态："+Thread.currentThread().isInterrupted());}}});t1.start();try {Thread.sleep(1000);} catch (InterruptedException e) {throw new RuntimeException(e);}t1.interrupt();}

控制台输出：

初始状态：false
被打断状态：true
复位返回值：true
复位后状态：false

2.由实验得出的结论：当catch注InterruptedException，JVM会认为程序已经处理了打断，会自动复位打断状态。代码：

public static void main(String[] args) {Thread t1 = new Thread(() -> {System.out.println("初始状态："+Thread.currentThread().isInterrupted());synchronized (WaitDemo.class) {try {WaitDemo.class.wait();} catch (InterruptedException e) {System.out.println("被打断状态："+Thread.currentThread().isInterrupted());// 复位boolean interrupted = Thread.interrupted();System.out.println("复位返回值："+interrupted);}System.out.println("复位后状态："+Thread.currentThread().isInterrupted());}});t1.start();try {Thread.sleep(1000);} catch (InterruptedException e) {throw new RuntimeException(e);}t1.interrupt();}

控制台输出：

初始状态：false
被打断状态：false
复位返回值：false
复位后状态：false

三、什么方法被打断会抛出InterruptedException

• sleep()
• wait()
• join()

四、能否打断BLOCK状态

不可以，代码：

public static void main(String[] args) throws InterruptedException {Thread t1 = new Thread(() -> {synchronized (args) {try {Thread.sleep(5000);} catch (InterruptedException e) {System.out.println("被打断了");}}});t1.start();Thread t2 = new Thread(() -> {synchronized (args) {}System.out.println("输出t2");});t2.start();Thread.sleep(1000);t2.interrupt();}

程序执行结果：5秒后才输出t2，证明t2没有被打断

五、能否打断Lock.lock()

lock()方法并不能被打断。与synchronized同理
但lockInterruptibly()方法可以被打断。
代码：

public static void main(String[] args) throws InterruptedException {Lock lock = new ReentrantLock();Thread t1 = new Thread(() -> {lock.lock();System.out.println("输出t1");try {Thread.sleep(10000);} catch (InterruptedException e) {System.out.println("t1被打断了");}lock.unlock();});t1.start();Thread t2 = new Thread(() -> {try {lock.lockInterruptibly();} catch (InterruptedException e) {System.out.println("t2被打断了");}System.out.println("输出t2");});t2.start();Thread.sleep(2000);t2.interrupt();}