java设计模式10 ---- 生产者-消费者模式[线程]

太过爱你忘了你带给我的痛 2022-05-21 13:13 204阅读 0赞

需求: 模拟两个 /多个 线程的--沟通协作(一个生产者线程, 一个消费者线程), 如何保证他们正常通信?

一, 两个线程的通信

![70][]

角色1--两个线程的工作目标: 中间物

/**
     * 角色: 
     * 1,中间物: name, falg
     * 2,生产者: flag, 中间物, getName()
     * 3,消费者: flag, 中间物, setName()
     * @author wang
     *
     */
    
    public class Food {
    	//属性
    	private String status;
    	private boolean isSetted;
    	//构造
    	public Food(String status) {
    		this.status = status;
    	}
    	
    	//方法1
    	//get(),set()
    	public synchronized void showName() {
    		
    		//判断p是否--isSetted
    		if(isSetted) {
    			System.out.println(Thread.currentThread().getName()+"say: "+status);
    			isSetted=false;//更换p的状态
    			notify();//通知生产者--可以生产了
    		}
    		else {
    			try {
    				wait();//休息等待
    			} catch (InterruptedException e) {
    			}
    		}
    	}
    	
    	int i=0;
    	public synchronized void setName() {
    		
    		//判断是否: isSetted
    		if(isSetted) {
    			try {
    				wait();//休息等待
    			} catch (InterruptedException e) {
    			}
    		}
    		else {
    			System.out.println(Thread.currentThread().getName()+"start work...\n\n");
    			//赋值
    			if(i++ %2==0) {
    				status="food status--too salty !!!";
    			}else {
    				status="food status--too sweaty !";
    			}
    			isSetted=true;//更换p的状态
    			notify();//通知其他线程--可以访问了
    		}//else
    	}
    }

角色2: 生产者线程

public class Producer implements Runnable {
    	//属性
    	private Food p;
    	//构造
    	public Producer(Food p) {
    		this.p = p;
    	}
    	
    	@Override
    	public void run() {
    		while(true)
    		p.setName();
    	}
    }

角色3: 消费者线程

public class Consumer implements Runnable {
    	//属性
    	private Food p;
    	
    	//构造
    	public Consumer(Food p) {
    		this.p = p;
    	}
    	
    	@Override
    	public void run() {
    		while(true)
    		p.showName();
    	}
    }

测试类

public class Test {
    	public static void main(String[] args) {
    		Food p = new Food("a");
    		Producer pro = new Producer(p);
    		Consumer cons = new Consumer(p);
    		
    		//启动线程
    		new Thread(pro,"生产者").start();
    		new Thread(cons,"消费者").start();
    	}
    }

==========截图验证=======

![70 1][]

二, 多个线程的通信

角色1:  所有线程--作用的对象(中间物): Food

/**
     *1,定义"菜" class: make(), clear()
     *2,定义生产者 class implements Runnable:  run(  菜.make()  ) 
     *3,定义消费者 class implements Runnable:  run(  菜.clear() )
    
     * 为了便于观察:  消费--生产线程: 的效果, 此处使用死循环--来多次操作
     * "游戏"规则:
     *  1, 顾客	 一次吃   1个food 
     *  2, 生产者 一次make 2个food
     * @author wang
     *
     */
    public class Food {
    	//属性
    	int foodCount;//food总数量
    	//构造
    	public Food(int foodCount) {
    		this.foodCount = foodCount;
    	}
    	
    	//方法1,对外提供的调用"接口": 如何制作菜
    	public synchronized void make() throws InterruptedException {
    		if(foodCount<5) {
    			int former=foodCount;
    			foodCount+=2;
    			System.out.println("\t foodCount="+former+",\t "+Thread.currentThread().getName()+"  又生产了2个food ! ==>foodCount="+foodCount);
    			this.notify();//通知顾客来吃
    		}
    		else {//休息等待
    			this.wait();
    		}
    	}
    	
    	//方法2,//对外提供的调用"接口": 如何销毁菜
    	public synchronized void clear() throws InterruptedException {
    		if(foodCount!=0) {
    			int former=foodCount;
    			foodCount--;
    			Thread.sleep(1000);//1s 消灭 一个
    			System.out.println("foodCount="+former+",\t "+Thread.currentThread().getName()+" 又消灭了1个food ! ==>foodCount="+foodCount);
    
    			this.notify();//通知生产者--已经吃完1个了
    		}
    		else {
    			this.wait();
    		}
    	}
    
    }

角色2:  生产者线程

public class Producer implements Runnable {
    	//属性
    	private Food f;
    	
    	//构造
    	public Producer(Food f) {
    		this.f = f;
    	}
    
    	@Override
    	public void run() {
    		
    		while(true) //一直调方法
    			try {
    				f.make();
    			} catch (InterruptedException e) {
    			}
    	}
    }

角色3:  消费者线程

public class Consumer implements Runnable {
    	//属性
    	Food f;
    	//构造
    	public Consumer(Food f) {
    		this.f = f;
    	}
    
    	
    	@Override
    	public void run() {
    		while(true) //一直调方法
    			try {
    				f.clear();
    			} catch (InterruptedException e) {
    			}
    	}
    }

测试类: 创建多个生产者, 多个消费者

public class Test {
    	public static void main(String[] args) {
    		Food f = new Food(5);
    		Producer sed1 = new Producer(f);
    		Consumer sed2 = new Consumer(f);
    		
    		Thread p1 = new Thread(sed1,"生产者1");
    		Thread p2 = new Thread(sed1,"生产者2");
    		Thread c1 = new Thread(sed2, "消费者1");
    		Thread c2 = new Thread(sed2, "消费者2");
    		Thread c3 = new Thread(sed2, "消费者3");
    		Thread c4 = new Thread(sed2, "消费者4");
    		Thread c5 = new Thread(sed2, "消费者5");
    		
    		//
    		p1.start();
    		p2.start();
    		c1.start();
    		c2.start();
    		c3.start();
    		c4.start();
    		c5.start();
    	}
    }

=========效果截图=======

![70 2][]

[70]: /images/20220521/7df8c6961baf48f299aa81b3b04c9b0d.png
[70 1]: /images/20220521/cbd912b03a0b4b3e9232c29e120682b8.png
[70 2]: /images/20220521/0d3144cf55c748cfb7fc57d98ca69bf4.png