线程知识总结2

参考文档：https://blog.csdn.net/weixin_45860338/article/details/113824249

B站：遇见狂神说

案例：线程停止

/**
 * 测试stop
 * 1.建议线程正常停止-->利用次数,不建议死循环
 * 2.建议使用标志位-->设置一个标志位
 * 3.不要使用stop或者destroy等过时或者JDK不建议使用的方法
 */
public class Demo15_StopThread implements Runnable {
    // 1. 设置一个标志位
    private boolean flag = true;

    @Override
    public void run() {
        int i = 0;
        while (flag) {
            System.out.println("run...Thread" + i++);
        }
    }

    // 2. 设置一个公开的方法停止线程,转换标志位
    public void stop() {
        this.flag = false;
    }

    public static void main(String[] args) {
        Demo15_StopThread stop = new Demo15_StopThread();
        new Thread(stop).start();
        for (int i = 0; i < 1000; i++) {
            System.out.println("main..." + i);
            if (i == 900) {
                //调用stop()切换标志位,让线程终止
                stop.stop();
                System.out.println("该线程停止了");
            }
        }
    }
}

线程休眠：

/**
 * 模拟网络延迟:放大问题的发生性
 */
public class Demo16_SleepThread implements Runnable {

    //票数
    private int ticketNums = 10;

    @Override
    public void run() {
        while (true) {
            if (ticketNums <= 0) {
                break;
            }
            //捕获异常
            try {
                Thread.sleep(200);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println(Thread.currentThread().getName() + "--->拿到了第" + ticketNums-- + "张票");
        }
    }

    public static void main(String[] args) {
        Demo4_TrainTicketsCase ticket = new Demo4_TrainTicketsCase();
        new Thread(ticket, "小红").start();
        new Thread(ticket, "老师").start();
        new Thread(ticket, "黄牛1").start();
    }
}

/**
 * 模拟倒计时
 */
public class Demo17_SleepThread2 {

    public static void main(String[] args) {
        try {
            tenDown();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    //模拟倒计时
    public static void tenDown() throws InterruptedException {
        int num = 10;//10秒
        while (true) {
            Thread.sleep(1000);
            System.out.println(num--);
            if (num <= 0) {
                break;
            }
        }
    }
}

/**
 * 每一秒获取当前时间
 */
public class Demo18_SleepThread3 {

    public static void main(String[] args) {
        //获取系统当前时间
        Date startTime = new Date(System.currentTimeMillis());
        while (true) {
            try {
                Thread.sleep(1000);
                //更新系统时间
                System.out.println(new SimpleDateFormat("HH:mm:ss").format(startTime));
                startTime = new Date(System.currentTimeMillis());
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}

礼让线程：

/**
 * 测试礼让线程
 * 礼让不一定成功,看cpu心情
 */
public class Demo19_YieldThread {
    public static void main(String[] args) {
        MyYeild myYeild = new MyYeild();
        new Thread(myYeild, "a").start();
        new Thread(myYeild, "b").start();
    }
}

class MyYeild implements Runnable {
    @Override
    public void run() {
        System.out.println(Thread.currentThread().getName() + "线程开始执行");
        Thread.yield();//礼让
        System.out.println(Thread.currentThread().getName() + "线程停止执行");
    }
}

 

线程插队：

/**
 * 测试join
 * 插队
 */
public class Demo20_JoinThread implements Runnable {
    @Override
    public void run() {
        for (int i = 0; i < 500; i++) {
            System.out.println("线程vip" + i);
        }
    }

    public static void main(String[] args) throws InterruptedException {
        //启动我们的线程
        Demo20_JoinThread joinThread = new Demo20_JoinThread();
        Thread thread = new Thread(joinThread);
        thread.start();

        //主线程
        for (int i = 0; i < 500; i++) {
            if (i == 200) {
                thread.join();//插队
            }
            System.out.println("main" + i);
        }
    }
}

观测线程状态：

/**
 * 观察测试线程状态
 */
public class Demo21_ThreadState {
    public static void main(String[] args) throws InterruptedException {
        Thread thread = new Thread(() -> {
            for (int i = 0; i < 5; i++) {
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
            System.out.println("//");
        });
        //观察状态
        Thread.State state = thread.getState();
        System.out.println(state);
        //观察启动后
        thread.start();
        state = thread.getState();
        System.out.println(state);//Run
        while (state != Thread.State.TERMINATED) {//只要现成不终止,就一直输出状态
            Thread.sleep(100);
            state = thread.getState();//更新线程状态
            System.out.println(state);
        }
        //死亡后的线程不能再启动了,启动会报异常
        //thread.start();
    }
}

/**
 * 线程优先级
 */
public class Demo22_ThreadPriority{
    public static void main(String[] args) {
        //主线程默认优先级
        System.out.println(Thread.currentThread().getName()+"-->"+Thread.currentThread().getPriority());

        MyPriority myPriority = new MyPriority();
        Thread thread1 = new Thread(myPriority);
        Thread thread2 = new Thread(myPriority);
        Thread thread3 = new Thread(myPriority);
        Thread thread4 = new Thread(myPriority);
        Thread thread5 = new Thread(myPriority);

        //先设置优先级,再启动
        thread1.start();

        thread2.setPriority(1);
        thread2.start();

        thread3.setPriority(4);
        thread3.start();

        thread4.setPriority(Thread.MAX_PRIORITY);//MAX_PRIORITY=10
        thread4.start();

        thread5.setPriority(8);
        thread5.start();
    }
}
class MyPriority implements Runnable{
    @Override
    public void run() {
        System.out.println(Thread.currentThread().getName()+"-->"+Thread.currentThread().getPriority());
    }
}

/**
 * 测试守护线程
 * 上帝守护你
 */
public class Demo23_DaemonThread {
    public static void main(String[] args) {
        God god = new God();
        You you = new You();

        Thread thread = new Thread(god);
        //默认false表示是用户线程,正常的线程都是用户线程...
        thread.setDaemon(true);
        //上帝守护线程启动
        thread.start();
        //你 用户线程启动
        new Thread(you).start();
    }
}

//上帝
class God implements Runnable{
    @Override
    public void run() {
        while (true){
            System.out.println("上帝保佑着你");
        }
    }
}

//你
class You implements Runnable{
    @Override
    public void run() {
        for (int i = 0; i < 36500; i++) {
            System.out.println("你一生都开心的活着");
        }
        System.out.println("====goodbye!world====");
    }
}