线程不安全的两个例子

1. 购买车票：

package Thread;


public class UnSafeBuyTicket {
    public static void main(String[] args) {
        BuyTicket buyTicket=new BuyTicket();
        new Thread(buyTicket,"李四").start();
        new Thread(buyTicket,"王五").start();
        new Thread(buyTicket,"黄牛").start();
    }
}

class BuyTicket implements Runnable{
    private int ticketNums=10;
    boolean flag=true;
    @Override
    public void run() {
        while (flag) {
            try {
                buy();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
    public void buy() throws InterruptedException {
        if (ticketNums <= 0) {
            flag=false;
            return;
        }
        Thread.sleep(10);
        System.out.println(Thread.currentThread().getName()+"拿了"+ticketNums--);
    }
}

2. 银行取钱

package Thread;

public class UnSafeBank {
    public static void main(String[] args) {
        Acount acount = new Acount(100, "结婚基金");
        Drawing you = new Drawing(acount, 50, "你");
        Drawing girlFriend = new Drawing((acount), 100, "老婆");
        you.start();
        girlFriend.start();
    }
}

//账户
class  Acount{
    int money;//余额
    String name;  //卡名

    public Acount(int money, String name) {
        this.money=money;
        this.name=name;
    }
}
//银行，模拟取钱
class Drawing extends Thread{
    Acount acount; //账户
    int drawingMoney; //取的钱
    int nowMoney;   //现在手里有多少钱

    public Drawing(Acount acount, int drawingMoney, String name) {
        super(name);
        this.acount=acount;
        this.drawingMoney=drawingMoney;
    }
    //取钱
    @Override
    public void run(){
        //判断有没有钱
        if (acount.money - drawingMoney < 0) {
            System.out.println(Thread.currentThread().getName() + "余额不足");
            return;
        }
        //sleep可以放大问题的发生性
        try {
            Thread.sleep(100);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        acount.money-=drawingMoney;
        nowMoney+=drawingMoney;
        System.out.println(acount.name + "余额为：" + acount.money);
        //Thread.currentThread().getName()=this.getName();  等号两边都是取得当前线程名。this指当前类对象。
        System.out.println(this.getName()+"手里的钱"+nowMoney);
    }
}