多线程安全卖票问题

package com.atjava.test;

class WindowRun implements Runnable{

    private int ticket = 100;
    @Override
    public void run() {
        while (true){
            if(ticket > 0){
                try {
                    Thread.sleep(100);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                System.out.println(Thread.currentThread().getName()+"卖票，票号为：" + ticket);
                ticket--;
            }else {
                break;
            }
        }
    }
}

public class WinTest{
    public static void main(String[] args) {
        WindowRun windowRun = new WindowRun();
        Thread thread1 = new Thread(windowRun);
        Thread thread2 = new Thread(windowRun);
        Thread thread3 = new Thread(windowRun);
        thread1.setName("窗口一");
        thread2.setName("窗口二");
        thread3.setName("窗口三");
        thread1.start();
        thread2.start();
        thread3.start();
    }
}

　　开发优先选择实现runnable接口，继承只能继承一个，实现多个

解决线程安全问题

package com.atjava.test;

class WindowRun implements Runnable{

    private int ticket = 100;
    private Object obj = new Object();
    @Override
    public void run() {
        while (true){
            synchronized (obj){
                if(ticket > 0){
                    try {
                        Thread.sleep(50);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    System.out.println(Thread.currentThread().getName()+"卖票，票号为：" + ticket);
                    ticket--;
                }else {
                    break;
                }
            }
        }
    }
}

public class WinTest{
    public static void main(String[] args) {
        WindowRun windowRun = new WindowRun();
        Thread thread1 = new Thread(windowRun);
        Thread thread2 = new Thread(windowRun);
        Thread thread3 = new Thread(windowRun);
        thread1.setName("窗口一");
        thread2.setName("窗口二");
        thread3.setName("窗口三");
        thread1.start();
        thread2.start();
        thread3.start();
    }
}

　　obj作为锁，锁的要求是多个线程共用一把锁，new了一次window，new 了一次Object

 

二、使用同步方法解决线程安全问题 synchronized  void sale(),省去了写同步监视器，如果普通方法锁默认为this.

如果静态方法锁为当前类