多线程（同步、结束）

 同步

package attribute;

public class SaleGoods implements Runnable {
    private int num=10;
    public synchronized void sellGoods(){
        if(num>0){
            System.out.println(Thread.currentThread().getName()+"正在出售第"+num+"件商品，"+"还剩"+(--num)+"件商品");
        }else {
            System.out.println("商品出售完了");
        }
    }
    public void run() {
        while (num > 0) {
            sellGoods();
            try {
                Thread.sleep(100);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}

package attribute;

public class TestSaleGoods {
    public static void main(String[] args){
        SaleGoods sell=new SaleGoods();
        Thread t1=new Thread(sell,"窗口1");
        Thread t2=new Thread(sell,"窗口2");
        Thread t3=new Thread(sell,"窗口3");
        Thread t4=new Thread(sell,"窗口4");
        t1.start();
        t2.start();
        t3.start();
        t4.start();
    }
}

运行结果

 结束

package attribute;

public class Demo extends Thread{
    boolean flag=true;
    @Override
    public void run() {
        if (flag) {
            try {
                Thread.sleep(1000*60);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println("分支线程开始干活！");
        }else
        {
            return;
        }
    }
}

package attribute;

public class Test {
    public static void main(String[] args) throws InterruptedException {
        Demo t=new Demo();
        t.start();
        t.flag=false;
        for (int i=0;i<5;i++){
            Thread.sleep(100);
            System.out.println("分支线程在休眠！------"+i+"秒");
        }
    }
}