Java多线程（四）------多线程打印数字练习题

问题描述：

   启动3个线程打印递增的数字, 线程1先打印1,2,3,4,5 然后是线程2打印6,7,8,9,10，然后是线程3打印11,12,13,14,15.接着再由线程1打印16,17,18,19,20....以此类推, 直到打印到75

代码：

package com.example.demo.threadTest;

import java.util.concurrent.BlockingQueue;
import java.util.concurrent.linkedBlockingQueue;


public class Test5 {
    static boolean flag1 = true;//控制线程切换
    static boolean flag2 = true;//控制线程切换
    static int num = 0;//资源临界值

    public static void main(String[] args) {
        //使用同一锁
        PrintIncreasingNums printIncreasingNums = new PrintIncreasingNums();
        //定义三个线程
        Thread thread1 = new Thread(printIncreasingNums, "线程一");
        Thread thread2 = new Thread(printIncreasingNums, "线程二");
        Thread thread3 = new Thread(printIncreasingNums, "线程三");
        //启动线程
        thread1.start();
        thread2.start();
        thread3.start();

    }
}

//打印递增数字
class PrintIncreasingNums implements Runnable {

    @Override
    public void run() {
        while (Test5.num <= 75) {
            if (Test5.flag1&&Test5.flag2&&Thread.currentThread().getName().equals("线程一")) {
                temp();
                Test5.flag2=false;
            }else if(Test5.flag1&&!Test5.flag2&&Thread.currentThread().getName().equals("线程二")){
                temp();
                Test5.flag1=false;
            }else if(!Test5.flag1&&!Test5.flag2&&Thread.currentThread().getName().equals("线程三")){
                temp();
                Test5.flag1=true ;
                Test5.flag2=true ;
            }
        }
    }

    public void temp(){
        //用锁控制递增的数字
        synchronized (this) {
            if (Test5.num == 75) {
                System.exit(0);
            }
            System.out.print(Thread.currentThread().getName() + "正在打印数字：");
            for (int i = Test5.num + 1; i <= Test5.num + 5; i++) {
                System.out.print(i + " ");
                //当为5的倍数
                if (i == Test5.num + 5) {
                    Test5.num = Test5.num + 5;
                    break;
                }
            }
            System.out.println();
        }
    }
}