wait notify

 

wait和notify是线程间通讯时用到。最典型的就是生产者消费者模型。

wait和notify要想运行成功，必须是相对于同一个对象锁而言的。

即用synchronized(obj)这个方法时，此obj必须是同一个obj.

否则wait和notify无法协调完成工作。

注意：notify是不阻塞的，只有wait才是阻塞的。只阻塞当前线程。一个形象的比喻就是，生产者不断的往房间里面扔东西，扔完一个就鬼喊一下快来取(container.notify),但是他自身不阻塞，还是继续往房间里扔东西。同时消费者不一定有能力来做，待CPU时间片轮到它时，它才来做。

 

consume代码：

package ProductAndConsume;

import java.util.List;

public class Consume implements Runnable {
	private List container = null;
	private int count;

	public Consume(List lst) {
		this.container = lst;
	}

	public void run() {
		while (true) {
			synchronized (container) {
				if (container.size() == 0) {
					try {
						container.wait();// 放弃锁
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
				}
				try {
					Thread.sleep(100);
				} catch (InterruptedException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
				container.remove(0);
				container.notify();
				System.out.println(Thread.currentThread().getName()+"^_^我吃了编号为" + (++count));
			}

		}
	}
}

 

 

2、product代码：

package ProductAndConsume;

import java.util.List;

public class Product implements Runnable {
	private List container = null;
	private int count;

	public Product(List lst) {
		this.container = lst;
	}

	@SuppressWarnings("unchecked")
	public void run() {
		while (true) {
			synchronized (container) {
				if (container.size() > MultiThread.MAX) {
					try {
						container.wait();
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
				}
				try {
					Thread.sleep(100);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
				container.add(new Object());
				container.notify();
				System.out.println(Thread.currentThread().getName()+"^_^我生产的编号为" + (++count));
			}
		}
	}
}

 

3、MultiThread代码：

package ProductAndConsume;

import java.util.ArrayList;
import java.util.List;

public class MultiThread {
	private List container = new ArrayList();
	public final static int MAX = 5;

	public static void main(String args[]) {
		MultiThread m = new MultiThread();
		new Thread(new Consume(m.getContainer())).start();
		new Thread(new Product(m.getContainer())).start();
	}

	public List getContainer() {
		return container;
	}

	public void setContainer(List container) {
		this.container = container;
	}
}

 

 

 

 

 

refurl:http://blog.sina.com.cn/s/blog_62dfe3ca0100k9tf.html

 

http://longdick.iteye.com/blog/453615