原创转载请注明出处:http://agilestyle.iteye.com/blog/2359893
Method in Java Doc
调用interrupt()方法仅仅是在当前线程中打了一个停止的标记,并不是真正的停止线程
package org.fool.java.concurrent.interrupt; public class InterruptTest1 { public static void main(String[] args) { try { Thread thread = new Thread(new MyThread()); thread.start(); Thread.sleep(5000); thread.interrupt(); } catch (InterruptedException e) { System.out.println("main catch"); e.printStackTrace(); } } public static class MyThread implements Runnable { @Override public void run() { for (int i = 0; i < 200000; i++) { System.out.println("i = " + (i + 1)); } } } }
Console Output
Note:
从运行结果来看,调用interrupt方法并没有停止线程
interrupted()
测试当前线程是否已经中断
package org.fool.java.concurrent.interrupt; public class InterruptTest2 { public static void main(String[] args) { try { Thread thread = new Thread(new MyThread()); thread.start(); Thread.sleep(1000); thread.interrupt(); System.out.println("is interrupted 1: " + thread.interrupted()); System.out.println("is interrupted 2: " + thread.interrupted()); } catch (InterruptedException e) { System.out.println("main catch"); e.printStackTrace(); } } public static class MyThread implements Runnable { @Override public void run() { for (int i = 0; i < 50000; i++) { System.out.println("i = " + (i + 1)); } } } }
Console Output
Note:
从控制台打印的结果来看,线程并未停止,这也证明了interrupted()方法的解释:测试当前线程是否已经中断。本例中这个“当前线程”是main,它从未中断过,所以打印的结果是两个false
修改Main函数
package org.fool.java.concurrent.interrupt; public class InterruptTest3 { public static void main(String[] args) { try { Thread thread = new Thread(new MyThread()); thread.start(); Thread.sleep(1000); Thread.currentThread().interrupt(); System.out.println(Thread.currentThread().getName()); System.out.println("is interrupted 1: " + Thread.currentThread().interrupted()); System.out.println("is interrupted 2: " + Thread.currentThread().interrupted()); } catch (InterruptedException e) { System.out.println("main catch"); e.printStackTrace(); } } public static class MyThread implements Runnable { @Override public void run() { for (int i = 0; i < 50000; i++) { System.out.println("i = " + (i + 1)); } } } }
Console Output
Note:
控制台第一次打印的结果是true,第二次为false;Java Doc中给出的解释是:测试当前线程是否已经中断,线程的中断状态由该方法清除。即如果连续两次调用该方法,则第二次调用将返回false(在第一次调用已清除flag后以及第二次调用检查中断状态之前,当前线程再次中断的情况除外)
所以,interrupted()方法具有清除状态flag的功能
isInterrupted()
测试线程是否已经中断
package org.fool.java.concurrent.interrupt; public class InterruptTest4 { public static void main(String[] args) { try { Thread thread = new Thread(new MyThread()); thread.start(); Thread.sleep(1000); thread.interrupt(); System.out.println("is interrupted 1: " + thread.isInterrupted()); System.out.println("is interrupted 2: " + thread.isInterrupted()); } catch (InterruptedException e) { System.out.println("main catch"); e.printStackTrace(); } } public static class MyThread implements Runnable { @Override public void run() { for (int i = 0; i < 200000; i++) { System.out.println("i = " + (i + 1)); } } } }
Console Output
is interrupted 1: true
is interrupted 2: true
Note:
isInterrupted()并未清除状态flag,所以打印两个true
Summary
interrupted(): 测试当前线程是否已经是中断状态,执行后具有清除中断状态flag的功能
isInterrupted(): 测试线程Thread对象是否已经是中断状态,但不清除中断状态flag
Reference
Java多线程编程核心技术 高洪岩 注