Java Synchronized与wait notify 连用

Java 两个线程同步感悟

//学习知识一定要学透彻，否则你你只是在一味地记忆知识

 

import java.util.Date;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;

import javax.swing.text.StyledEditorKit.ForegroundAction;

import org.omg.CORBA.PUBLIC_MEMBER;

class Resource{
	String name;
	String sex;
	boolean flag = false;
}


class Input implements Runnable
{
	Resource resource = new Resource();
	public Input(Resource resource){
		this.resource = resource;
	}
	
	public void run()
	{
		boolean flag = true;
		while(true){
			synchronized(resource){
				if(resource.flag){
					try {
						this.resource.wait();
					} catch (InterruptedException e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}
				}
				
				if(flag){
					this.resource.name = "mike";
					this.resource.sex = "man";
					flag = false;
				}
				else{
					this.resource.name = "Lili";
					this.resource.sex = "femal";
					flag = true;	
				}
				this.resource.notify();
				resource.flag = true;				
				
			}// synchronized				
		}//while
	}

}

class Output implements Runnable
{
	Resource resource = new Resource();
	public Output(Resource resource) {
		// TODO Auto-generated constructor stub
		this.resource = resource;
	}
	@Override
	public void run() {
		// TODO Auto-generated method stub
		while(true){
			synchronized (resource) {
				if(!resource.flag){
					try {
						this.resource.wait();
					} catch (InterruptedException e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}
				
					System.out.println(resource.name + "..." + resource.sex);
					resource.flag = false;
					resource.notify();
				}
			}
		}
	}
}

public class HeiMa {

	public static void main(String[] args){
		Resource resource = new Resource();
		Input input = new Input(resource);
		Output output = new Output(resource);
		
		Thread t1 = new Thread(input);
		Thread t2 = new Thread(output);
		
		t1.start();
		t2.start();
		
	}

}

我查看API 看到wait() 有这么一段说明： The current thread must own this object's monitor.

一直没有明白这句话倒是是什么意思。后来做了这个实例。刚开始我是这样写的程序

import java.util.Date;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;

import javax.swing.text.StyledEditorKit.ForegroundAction;

import org.omg.CORBA.PUBLIC_MEMBER;

class Resource{
	String name;
	String sex;
	boolean flag = false;
}


class Input implements Runnable
{
	Resource resource = new Resource();
	public Input(Resource resource){
		this.resource = resource;
	}
	
	public void run()
	{
		boolean flag = true;
		while(true){
			synchronized(resource.getClass()){
				if(resource.flag){
					try {
						this.resource.wait();
					} catch (InterruptedException e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}
				}
				
				if(flag){
					this.resource.name = "mike";
					this.resource.sex = "man";
					flag = false;
				}
				else{
					this.resource.name = "Lili";
					this.resource.sex = "femal";
					flag = true;	
				}
				this.resource.notify();
				resource.flag = true;				
				
			}// synchronized				
		}//while
	}

}

class Output implements Runnable
{
	Resource resource = new Resource();
	public Output(Resource resource) {
		// TODO Auto-generated constructor stub
		this.resource = resource;
	}
	@Override
	public void run() {
		// TODO Auto-generated method stub
		while(true){
			synchronized (resource.getClass()) {
				if(!resource.flag){
					try {
						this.resource.wait();
					} catch (InterruptedException e) {
						// TODO Auto-generated catch block
						e.printStackTrace();
					}
				
					System.out.println(resource.name + "..." + resource.sex);
					resource.flag = false;
					resource.notify();
				}
			}
		}
	}
}

public class HeiMa {

	public static void main(String[] args){
		Resource resource = new Resource();
		Input input = new Input(resource);
		Output output = new Output(resource);
		
		Thread t1 = new Thread(input);
		Thread t2 = new Thread(output);
		
		t1.start();
		t2.start();
		
	}

}

 

编译器给我报的是这个异常java.lang.IllegalMonitorStateException.Google一下没怎么明白，我又想起上面 wait的那段解释，就讲程序进行了修正。最终结果就正确的。这我说明你用 wait，notify，notifyall，必须和synchronized 锁同一个对象