java併發專題-談談ReentrantLock的lockInterruptibly方法

時間 2019-11-10

標籤 java 併發專題談談 reentrantlock lockinterruptibly 方法欄目 Java 简体版

原文原文鏈接

lockInterruptibly方法是說線程在等待獲取鎖的同時還能響應線程interrupt方法的中斷請求。換句話說就是存在等待獲取鎖的同時還不能響應線程interrupt方法的中斷請求的狀況，synchronized內置鎖即是，請看測試代碼：工具

public class LockInterruptTest {測試

   public static void main(String[] args) {
       // TODO Auto-generated method stub
       Thread t1 = new Thread(){
           public void run(){
               synchronized (LockInterruptTest.class) {
                   while(true){
                       try {
                           Thread.sleep(1000);
                       } catch (InterruptedException e) {
                           e.printStackTrace();
                       }
                   }
               }
           }
       };
       t1.start();
       try {
           Thread.sleep(1000);
       } catch (InterruptedException e1) {
           // TODO Auto-generated catch block
           e1.printStackTrace();
       }
       Thread t2 = new Thread(){
           public void run(){
               synchronized (LockInterruptTest.class) {
                   while(true){
                       try {
                           Thread.sleep(1000);
                       } catch (InterruptedException e) {
                           e.printStackTrace();
                       }
                   }
               }
           }
       };
       t2.start();
       try {
           Thread.sleep(1000);
       } catch (InterruptedException e1) {
           // TODO Auto-generated catch block
           e1.printStackTrace();
       }
       Thread t3 = new Thread(){
           public void run(){
               System.out.println("準備中斷t2");
               t2.interrupt();
               System.out.println("中斷t2");
           }
       };
       t3.start();
   }線程

}
代碼中準備了3個線程，第2個線程嘗試獲取第1個線程的鎖，第3個線程嘗試中斷第2個線程。代碼是可以正常看到「中斷t2」的，可是用jconsole工具就能看到第2個線程因爲嘗試獲取鎖一直阻塞着：blog

換成lockInterruptibly後代碼以下：io

public class LockInterruptTest {
static ReentrantLock lock = new ReentrantLock();console

   public static void main(String[] args) {
       Thread t1 = new Thread() {
           public void run() {
               try {
                   lock.lockInterruptibly();
               } catch (InterruptedException e1) {
                   e1.printStackTrace();
               }
               try {
                   while (true) {
                       try {
                           Thread.sleep(1000);
                       } catch (InterruptedException e) {
                           e.printStackTrace();
                       }
                   }
               } finally {
                   lock.unlock();
               }
           }
       };
       t1.start();
       try {
           Thread.sleep(1000);
       } catch (InterruptedException e1) {
           e1.printStackTrace();
       }
       Thread t2 = new Thread() {
           public void run() {
               try {
                   lock.lockInterruptibly();
                   while (true) {
                       try {
                           Thread.sleep(1000);
                       } catch (InterruptedException e) {
                           e.printStackTrace();
                       }
                   }
               } catch (InterruptedException e1) {
                   e1.printStackTrace();
               } finally {
                   lock.unlock();
               }
           }
       };
       t2.start();
       try {
           Thread.sleep(1000);
       } catch (InterruptedException e1) {
           e1.printStackTrace();
       }
       Thread t3 = new Thread() {
           public void run() {
               System.out.println("準備中斷t2");
               t2.interrupt();
               System.out.println("中斷t2");
           }
       };
       t3.start();
   }class