多线程访问共享区示例

Myth丶恋晨 2022-07-14 18:59 166阅读 0赞

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

//缓冲池（共享区）  
class Pool  
\{  
final Lock lock = new ReentrantLock();// 创建互斥锁  
// 分别将两个监听器绑定到同一个锁上。  
final Condition notFull = lock.newCondition();  
final Condition notEmpty = lock.newCondition();  
// 商品数组对象  
final Goods\[\] items = new Goods\[Goods.MAX\_SIZE\];  
// 下标，计数器  
int pro, con, count;

// 封装生产者方法
    public void product(Goods x) throws InterruptedException
    {
    lock.lock();
    try
    {
    
        while (count == Goods.MAX_SIZE)
        {
        notFull.await();
        }
        items[pro] = x;
        System.out.println("生产\"" + ++count + "\"号商品--名称："
            + items[pro].getName() + "--价格：" + items[pro].getPrice());
        if (++pro == Goods.MAX_SIZE)
        {
        pro = 0;
        }
    
        notEmpty.signal();
    }
    
    finally
    {
        lock.unlock();
    }
    }
    
    // 封装消费者方法
    public Goods consume() throws InterruptedException
    {
    lock.lock();
    try
    {
        while (count == 0)
        {
        notEmpty.await();
        }
        Goods goods = items[con];
        System.out.println("消费\"" + --count + "\"号商品--名称："
            + items[con].getName() + "--价格：" + items[con].getPrice());
        if (++con == Goods.MAX_SIZE)
        {
        con = 0;
        }
    
        notFull.signal();
        return goods;
    
    }
    finally
    {
        lock.unlock();
    }
    
    }

// 生产者  
class Producter implements Runnable  
\{  
private Pool p;  
private Goods g;

Producter(Pool p, Goods g)
    {
    this.p = p;
    this.g = g;
    }
    
    public void run()
    {
    while (true)
    {
        try
        {
        p.product(g);
        }
        catch (InterruptedException e)
        {
        // TODO Auto-generated catch block
        e.printStackTrace();
        }
    }
    }

// 消费者  
class Consumer implements Runnable  
\{  
Pool p;  
Goods g;

Consumer(Pool p, Goods g)
    {
    this.p = p;
    this.g = g;
    }
    
    public void run()
    {
    while (true)
    {
    
        try
        {
        p.consume();
        }
        catch (InterruptedException e)
        {
        // TODO Auto-generated catch block
        e.printStackTrace();
        }
    }
    }

// 商品  
class Goods  
\{  
static final int MAX\_SIZE = 100;  
private String name;  
private int price;

Goods(String name, int price)
    {
    this.name = name;
    this.price = price;
    }
    
    public String getName()
    {
    return name;
    }
    
    public int getPrice()
    {
    return price;
    }

public class Producter\_consumer  
\{

public static void main(final String[] args)
    {
    // 定义商品对象
    Goods bread = new Goods("面包", 10);
    // 创建资源
    Pool resource = new Pool();
    // 创建线程任务，生产和消费
    Producter productTask = new Producter(resource, bread);
    Consumer consumeTask = new Consumer(resource, bread);
    // 创建线程,两个生产者线程，两个消费者线程
    Thread t0 = new Thread(productTask);
    Thread t1 = new Thread(productTask);
    Thread t2 = new Thread(consumeTask);
    Thread t3 = new Thread(consumeTask);
    // 开启线程
    t0.start();
    t1.start();
    t2.start();
    t3.start();
    
    }