22.线程通讯Condition

Condition

    经过此对象能够与lock实现组合使用，为每一个对象提供多个等待，实现多个阻塞队列。

 
 
 
 
 

  
  
  
  
  
   
   
   
   
   

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

    
    
    
    
    

   
   
   
   
   
 
 
 
 
 
 
 
 
 
 
多Condition组合
 
 
 
 
 

  
  
  
  
  
 
   
    
    
    
    
    

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

     
     
     
     
     
 }
     
     
     
     
     

     
     
     
     
     

     
     
     
     
     

    
    
    
    
    
 
  
  
  
  
  
  

 
 
 
 
 
经常使用方法
 
 
 
 
 

  
  
  
  
  
 
   
 
   
 
   
 
   
 
   
 
   
 
   
 
   
 
   
 
   
 
   
 
   
  
  
 
 
 
 
 
package dmeo9;import java.util.concurrent.locks.Condition;import java.util.concurrent.locks.Lock;import java.util.concurrent.locks.ReentrantLock;public class DemoLock2 { private Lock lock = new ReentrantLock(); private Condition condition1 = lock.newCondition(); public void m1(){ try { lock.lock(); System.err.println(Thread.currentThread().getName()+"：线程，进入m1"); Thread.sleep(3000); System.err.println(Thread.currentThread().getName()+"：线程，释放锁，接收通唤醒知"); condition1.await(); System.err.println(Thread.currentThread().getName()+"：线程，继续执行 m1"); } catch (InterruptedException e) { e.printStackTrace(); }finally { lock.unlock(); } } public void m2(){ try { lock.lock(); System.err.println(Thread.currentThread().getName()+"：线程，进入m2"); Thread.sleep(3000); System.err.println(Thread.currentThread().getName()+"：线程，发出通知,唤醒"); condition1.signal(); System.err.println(Thread.currentThread().getName()+"：线程，继续执行 m2"); } catch (InterruptedException e) { e.printStackTrace(); }finally { lock.unlock(); } } public static void main(String[] atgs) { final DemoLock2 demoLock = new DemoLock2(); Thread t1 = new Thread(new Runnable() { @Override public void run() { demoLock.m1();; } },"消费者t1"); Thread t2 = new Thread(new Runnable() { @Override public void run() { demoLock.m2();; } },"生产者t2"); t1.start(); t2.start(); }}输出：消费者t1：线程，进入m1 消费者t1：线程，释放锁，接收通唤醒知 生产者t2：线程，进入m2 生产者t2：线程，发出通知,唤醒 生产者t2：线程，继续执行 m2 消费者t1：线程，继续执行 m1
package dmeo9;import java.util.concurrent.locks.Condition;import java.util.concurrent.locks.Lock;import java.util.concurrent.locks.ReentrantLock;/** * Created by liudan on 2017/8/4. */public class DemoLock3 { /** * 经过一对象产生lock对象，并生产多个Condition进行多线程的交互，能够作到一部分唤醒，另外一部分继续等待。 */ private Lock lock = new ReentrantLock(); private Condition condition1 = lock.newCondition(); private Condition condition2 = lock.newCondition(); public void m1() { try { lock.lock(); System.err.println(Thread.currentThread().getName() + "：进入m1"); Thread.sleep(100); System.err.println(Thread.currentThread().getName() + "：m1释放锁，接收通唤醒知"); condition1.await(); System.err.println(Thread.currentThread().getName() + "：继续执行 m1"); } catch (InterruptedException e) { e.printStackTrace(); } finally { lock.unlock(); } } public void m2() { try { lock.lock(); System.err.println(Thread.currentThread().getName() + "：进入m2"); Thread.sleep(200); System.err.println(Thread.currentThread().getName() + "：m2释放锁，接收通唤醒知"); condition1.await(); System.err.println(Thread.currentThread().getName() + "：继续执行 m2"); } catch (InterruptedException e) { e.printStackTrace(); } finally { lock.unlock(); } } public void m3() { try { lock.lock(); System.err.println(Thread.currentThread().getName() + "：进入m3"); Thread.sleep(300); System.err.println(Thread.currentThread().getName() + "：m3释放锁，接收通唤醒知"); condition2.await(); System.err.println(Thread.currentThread().getName() + "：继续执行 m3"); } catch (InterruptedException e) { e.printStackTrace(); } finally { lock.unlock(); } } public void m4() { try { lock.lock(); System.err.println(Thread.currentThread().getName() + "：进入m4"); Thread.sleep(400); System.err.println(Thread.currentThread().getName() + "：m4发出通知并唤醒：m一、m2"); condition1.signalAll(); } catch (InterruptedException e) { e.printStackTrace(); } finally { lock.unlock(); } } public void m5() { try { lock.lock(); System.err.println(Thread.currentThread().getName() + "：进入m5"); Thread.sleep(500); System.err.println(Thread.currentThread().getName() + "：m5发出通知并唤醒：m3"); condition2.signal(); } catch (InterruptedException e) { e.printStackTrace(); } finally { lock.unlock(); } } public static void main(String[] atgs) { DemoLock3 demoLock3 = new DemoLock3(); Thread t1 = new Thread(new Runnable() { @Override public void run() { demoLock3.m1(); } }, "_1"); Thread t2 = new Thread(new Runnable() { @Override public void run() { demoLock3.m2(); } }, "_2"); Thread t3 = new Thread(new Runnable() { @Override public void run() { demoLock3.m3(); } }, "_3"); Thread t4 = new Thread(new Runnable() { @Override public void run() { demoLock3.m4(); } }, "_4"); Thread t5 = new Thread(new Runnable() { @Override public void run() { demoLock3.m5(); } }, "_5"); t1.start(); t2.start(); t3.start(); try { Thread.sleep(3000); } catch (InterruptedException e) { e.printStackTrace(); } t4.start(); try { Thread.sleep(3000); } catch (InterruptedException e) { e.printStackTrace(); } t5.start();}输出：_1：进入m1 _1：m1释放锁，接收通唤醒知 _2：进入m2 _2：m2释放锁，接收通唤醒知 _3：进入m3 _3：m3释放锁，接收通唤醒知 _4：进入m4 _4：m4发出通知并唤醒：m一、m2 _1：继续执行 m1 _2：继续执行 m2 _5：进入m5 _5：m5发出通知并唤醒：m3 _3：继续执行 m3
 * 公平锁、非公平锁 * Lock lock = new ReentrantLock(boolean isFair)。 * tryLock()尝试去获取锁，并得到结果用false、true返回，并在给定的时间内去获取。 * isFair():是否公平锁。 * isLocked():是否锁定 * getHoldCount()：查询当前的线程保存的锁存在的个数，也就是调用lock的次数。 * lockinterruptibly():优先响应中断的锁。 * getQueueLength():返回正在等待获取此锁的线程数量。 * getWaitQueueLenth():获取返回等待与锁定相关的给定条件condition的线程数量。 * hasQueuedThread(Thread thread):查询指定的线程是否正在等待此锁。 * hasQueuedThread():查询是否有线程正在等待次锁。 * hasWaiters():查询是否有线程正在等待与此锁有关的condition条件。