java的wait和notifyAll使用方法

class Num
{
	private int num;
	public int getNum() {
		return num;
	}
	public void setNum(int num) {
		this.num = num;
	}
	public Num(int num)
	{
		this.num=num;
	}
}
class myThreadA extends Thread
{
	private Num num;
	public myThreadA(Num num)
	{
		this.num=num;
	}

	public void run()
	{
			while(true)
			{
				synchronized(num)
				{
					while(num.getNum()!=1)
						try {
							num.wait();
						} catch (InterruptedException e) {
							// TODO Auto-generated catch block
							e.printStackTrace();
						}

					System.out.println(1);
					num.setNum(2);
					num.notifyAll();
				}
			}

	}
}

class myThreadB extends Thread
{
	private Num num;
	public myThreadB(Num num)
	{
		this.num=num;
	}

	public void run()
	{
			while(true)
			{
				synchronized(num)
				{
					while(num.getNum()!=2)
						try {
							num.wait();
						} catch (InterruptedException e) {
							// TODO Auto-generated catch block
							e.printStackTrace();
						}

					System.out.println(2);
					num.setNum(1);
					num.notifyAll();
				}
			}

	}
}

public class test001 {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Num num=new Num(1);
		myThreadA a=new myThreadA(num);
		myThreadB b=new myThreadB(num);
		a.start();
		b.start();

	}

}

代码如上所看到的

输出内容例如以下

2

1

2

1

2

1

即重复输出1和2.这里我们就採用了线程的同步模式，一个线程输出1，另外一个线程输出2，而且可以进行同步，同步则是利用对象Num的wait和notifyAll来进行的。