二十一、三大不安全案例

1. 不安全买票

public class UnSafeBuyTicket {
    public static void main(String[] args) {
        BuyTicket buyTicket = new BuyTicket();
        new Thread(buyTicket,"张三").start();
        new Thread(buyTicket,"李四").start();
        new Thread(buyTicket,"王五").start();
    }
}
class BuyTicket implements Runnable{

    private int ticket=3;

    @Override
    public void run() {
        while (true){
            if(ticket>0){
                System.out.println(Thread.currentThread().getName()+"买到的票号为："+ticket--);
            }else{
                break;
            }
        }
    }
}

结果：

2. 不安全取钱

public class UnSafeBank {

    public static void main(String[] args) {
        Withdraw withdraw = new Withdraw(80);
        Thread t1=new Thread(withdraw,"他");
        Thread t2=new Thread(withdraw,"她");
        t1.start();
        t2.start();
    }
}

class Withdraw implements Runnable{

    //余额
    private int balance=100;

    //取出
    private int take;

    public Withdraw(int take) {
        this.take = take;
    }

    @Override
    public void run() {
        if (balance-take>0){
            try {
                if (Thread.currentThread().getName().equals("他")){
                    Thread.sleep(1000);
                }
            } catch (InterruptedException e) {
                throw new RuntimeException(e);
            }

            balance=balance-take;
            System.out.println(Thread.currentThread().getName()+"取出："+take+"，剩余："+balance);
        }else{
            System.out.println("余额不足");
        }

    }
}

结果：

3. 不安全列表（如：ArryList）

public class UnSafeList{

    public static void main(String[] args) {

        List list = new ArrayList();
        for (int i = 0; i < 2000; i++) {
            new Thread(()->{
                list.add(Thread.currentThread().getName());
            }).start();
        }
        System.out.println(list.size());
    }
}

结果：说明ArrayList并不是线程安全的，如果安全，则list.size()应该等与2000。

标签：Thread,start,int,二十一,案例,take,new,public,三大
来源： https://www.cnblogs.com/epiphany8/p/16272113.html