练习——简单的线程练习

package com.thread_;

import java.util.Scanner;

/*
在main方法中启动两个线程
第1个线程循环随机打印100以内的整数
直到第2个线程从键盘读取了“Q”命令。

 */
public class ThreadExercise {
    public static void main(String[] args) {
        A a = new A();
        B b = new B(a);
        a.start();
        b.start();
    }

}

class A extends Thread {
    private boolean loop = true;
    @Override
    public void run() {
        while (loop){
            System.out.println((int)(Math.random()*100 + 1));
            //休眠
            try {
                sleep(3000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    public void setLoop(boolean loop) {
        this.loop = loop;
    }
}

class B extends Thread {
    private A a;
    private Scanner scanner= new Scanner(System.in);
    public B(A a){
        this.a = a;
    }

    @Override
    public void run() {
        while (true){
        //接收键盘输入
        System.out.println("输入Q并回车停止打印");
        char str = scanner.next().toUpperCase().charAt(0);
        if (str == 'Q'){
                a.setLoop(false);
                break;
            }
        }
    }
}


package com.thread_;

/*
有2个用户分别从同一个卡上取钱(总额:10000)
每次都取1000,当余额不足时，就不能取款了
不能出现超取现象
 */
public class ThreadExercise2 {
    public static void main(String[] args) {
        User user = new User();
        Thread thread1 = new Thread(user);
        thread1.setName("user1");
        Thread thread2 = new Thread(user);
        thread2.setName("user2");
        thread1.start();
        thread2.start();
    }

}
//涉及多个线程共享资源，故实现Runnable接口
class User implements Runnable {
    private static int money = 10000;
    @Override
    public void run() {
        while (true){
            synchronized (this) {
                money -= 1000;
                System.out.println(Thread.currentThread().getName() + "取出1000元，" + "余额" + money);
            }
            try {
                Thread.sleep(100);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            if (money <= 0){
                System.out.println("余额不足！！！");
                break;
            }
        }
    }
}