Lock锁

import java.util.concurrent.locks.*;

class ProducerConsumerDemo2

{

public static void main(String[] args)

{

Resource r = new Resource();

Producer pro = new Producer(r);

Consumer con = new Consumer(r);

Thread t1 = new Thread(pro);

Thread t2 = new Thread(pro);

Thread t3 = new Thread(con);

Thread t4 = new Thread(con);

t1.start();

t2.start();

t3.start();

t4.start();

}

}

/*

JDK1.5 中提供了多线程升级解决方案。

将同步Synchronized替换成现实Lock操作。

将Object中的wait，notify notifyAll，替换了Condition对象。

该对象可以Lock锁 进行获取。

该示例中，实现了本方只唤醒对方操作。

Lock:替代了Synchronized

lock

unlock

newCondition()

Condition：替代了Object wait notify notifyAll

await();

signal();

signalAll();

*/

class Resource

{

private String name;

private int count = 1;

private boolean flag = false;

// t1 t2

private Lock lock = new ReentrantLock();

private Condition condition_pro = lock.newCondition();

private Condition condition_con = lock.newCondition();

public void set(String name)throws InterruptedException

{

lock.lock();

try

{

while(flag)

condition_pro.await();//t1,t2

this.name = name+”–”+count++;

System.out.println(Thread.currentThread().getName()+”…生产者..”+this.name);

flag = true;

condition_con.signal();

}

finally

{

lock.unlock();//释放锁的动作一定要执行。

}

}

// t3 t4

public void out()throws InterruptedException

{

lock.lock();

try

{

while(!flag)

condition_con.await();

System.out.println(Thread.currentThread().getName()+”…消费者………”+this.name);

flag = false;

condition_pro.signal();

}

finally

{

lock.unlock();

}

}

}

class Producer implements Runnable

{

private Resource res;

Producer(Resource res)

{

this.res = res;

}

public void run()

{

while(true)

{

try

{

res.set(“+商品+”);

}

catch (InterruptedException e)

{

}

}

}

}

class Consumer implements Runnable

{

private Resource res;

Consumer(Resource res)

{

this.res = res;

}

public void run()

{

while(true)

{

try

{

res.out();

}

catch (InterruptedException e)

{

}

}

}

}