多线程之3个线程之间的通信

import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;

public class Ticket02 {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Printer2 p2 = new Printer2();
		//开启线程
		new Thread(){
			public void run(){
				while(true){
					try {
						p2.print1();
					} catch (Exception e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}
				}
			}
		}.start();
		
		new Thread(){
			public void run(){
				while(true){
					try {
						p2.print2();
					} catch (Exception e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}
				}
			}
		}.start();
		
		new Thread(){
			public void run(){
				while(true){
					try {
						p2.print3();
					} catch (Exception e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}
				}
			}
		}.start();
	}

}

class Printer2{
	private ReentrantLock r = new ReentrantLock();
	private Condition c1 = r.newCondition();
	private Condition c2 = r.newCondition();
	private Condition c3 = r.newCondition();
	
	int flag = 1;
	//第一个方法
	public void print1() throws Exception{		
			r.lock();
			while(flag!=1){
				c1.await();
			}			
			System.out.println("b");
			flag = 2;
			c2.signal();
			r.unlock();		
	}
	
	public void print2() throws Exception{		
		r.lock();
		while(flag!=2){
			c2.await();
		}			
		System.out.println("a");
		flag = 3;
		c3.signal();
		r.unlock();
	}
	
	public void print3() throws Exception{		
		r.lock();
		while(flag!=3){
			c3.await();
		}			
		System.out.println("c");
		flag = 1;
		c1.signal();
		r.unlock();	
	}
}