三个线程交替打印数字demo

 

  代码如下，注释写的非常详细，复制就能跑。

 
 

public class Xs02 {
    //用volatile修饰了两个一会要用到的int
    private volatile int flag=0;
    private volatile int work=0;
    private Thread t1,t2,t3;

    public static void main(String[] args) {
        Xs02 xs02 = new Xs02();
        //启动
        xs02.ts();
    }

    private void ts(){
        //启动线程的方法，这一步直接写在main方法也行
        t1=new Thread(new a());
        t2=new Thread(new b());
        t3=new Thread(new c());
        t1.start();
        t2.start();
        t3.start();
    }
    private class a implements Runnable{
        @Override
        public void run() {
            //先判断要打印的数字是否达到阈值，没有才继续打印
            while (work<=100){
                //这里是用volatile给每个线程都做了一个专属标志位，只有该变量为指定值时，对应的线程才打印数字
                if(flag==0){
                    //如果为指定值就打印数字
                    System.out.println("1:"+work++);
                    //打印完后，修改为下一个线程的标志位
                    flag=1;
                }
            }
        }
    }

    private class b implements Runnable{
        @Override
        public void run() {
            while (work<=100){
                if(flag==1){
                    System.out.println("2:"+work++);
                    flag=2;
                }
            }
        }
    }

    private class c implements Runnable{
        @Override
        public void run() {
            while (work<=100){
                if(flag==2){
                    System.out.println("3:"+work++);
                    flag=0;
                }
            }
        }
    }
}