java多线程通信 例子

package com.cl.www.thread;

public class NumberHolder {
    
    private Integer number = 0;
    
    // 增加number
    public synchronized void increaseNum(){
        //不是0就不加
        while(number != 0){   
            try {
                this.wait();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        number++;
        System.out.println("number的值为："+number);
        this.notifyAll(); //通知其它线程
    }
    
    //减少number
    public synchronized void decreaseNum(){
        //如果等于0就不减少
        while(number == 0){
            try {
                this.wait();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        number--;
        System.out.println("number的值为："+number);
        this.notifyAll(); //通知其它线程
    }
}

package com.cl.www.thread;
/**
 * 
 * 增加number
 */
public class IncreaseThread implements Runnable{
    
    private NumberHolder numberHolder;
    
    public IncreaseThread(NumberHolder numberHolder) {
        this.numberHolder = numberHolder;
    }

    @Override
    public void run() {
        int i = 0;
        while(i<10){
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            numberHolder.increaseNum();
            i++;
        }
    }
}

package com.cl.www.thread;

/**
 * 减少number
 *
 */
public class DecreaseThread implements Runnable{
    
    private NumberHolder numberHolder;
    
    public DecreaseThread(NumberHolder numberHolder) {
        
        this.numberHolder = numberHolder;
    }
    @Override
    public void run() {
        int i =0;
        while(i<10){
            try {
                Thread.sleep((long)Math.random()*1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            numberHolder.decreaseNum();
            i++;
        }
    }
}

package com.cl.www.thread;

public class MainTest {
    public static void main(String[] args) {
        
        NumberHolder numberHolder = new NumberHolder();
        
        IncreaseThread increaseThread = new IncreaseThread(numberHolder);
        DecreaseThread decreaseThread = new DecreaseThread(numberHolder);
        
        Thread th1 = new Thread(increaseThread);   // 加 number
        Thread th2 = new Thread(decreaseThread);   // 减 number
        
        Thread th3 = new Thread(increaseThread);    // 加 number
        Thread th4 = new Thread(decreaseThread);    // 减 number
        
        th1.start();
        th2.start();
        
        th3.start();
        th4.start();
    }
}

输出结果