多线程之间的通信 唤醒指定线程

class Out {
	private int i = 1;
	private ReentrantLock r = new ReentrantLock();//锁对象
	private Condition c1 = r.newCondition();//
	private Condition c2 = r.newCondition();
	private Condition c3 = r.newCondition();
	
	
	public void out1() throws InterruptedException {
 
		r.lock();
			if (i != 1) {//因为是唤醒或等待指定线程,只需判断一次
				c1.await();//c1等待
			}
			Thread.sleep(1000);
			System.out.println("1号线程");
			i = 2;
			c2.signal();//c2唤醒
		r.unlock();

	}

	public void out2() throws InterruptedException {

		r.lock();
			if (i != 2) {
				c2.await();
			}
			Thread.sleep(1000);
			System.out.println("2号线程");
			i = 3;
			c3.signal();
		r.unlock();

	}

	public void out3() throws InterruptedException {

		r.lock();
			if (i != 3) {
				c3.await();
			}
			Thread.sleep(1000);
			System.out.println("3号线程");
			i = 1;
			c1.signal();
		r.unlock();

	}
}

class hello {

	public static void main(String[] args) throws IOException, InterruptedException {
		Out o = new Out();
		new Thread() {
			public void run() {
				while (true) {
					try {
						o.out1();
					} catch (InterruptedException e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}
				}
			}
		}.start();
		new Thread() {
			public void run() {
				while (true) {
					try {
						o.out2();
					} catch (InterruptedException e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}
				}
			}
		}.start();
		new Thread() {
			public void run() {
				while (true) {
					try {
						o.out3();
					} catch (InterruptedException e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}
				}
			}
		}.start();
	}
}

运行结果: