synchronized保证线程安全

package com.Java;

//银行不安全案例 两个人同时取钱
//使用 synchronized和synchronized块 可以锁住对象 保证线程的安全性
public class TestBank {
    public static void main(String[] args) {

        Account account = new Account(50);
        Drawing you = new Drawing(account, 50, "你");
        Drawing youGirl = new Drawing(account, 50, "你妻子");
        new Thread(you).start();

        new Thread(youGirl).start();

    }
}

class Account {
    int money; //手里有多少钱

    public Account(int money) {
        this.money = money;
    }
}

class Drawing extends Thread {

    private Account account;    //账户
    int drawing; //取款多少钱

    public Drawing(Account account, int drawing, String name) {
        super(name);//把名字传给Thread  这里相当于getName的值
        this.account = account;
        this.drawing = drawing;
    }

    @Override
    public /*synchronized*/ void run() {    //synchronized 指人对象默认是this  即当前所在类的对象
        synchronized (account) { //synchronized块可以锁指定对象
            if (account.money - drawing < 0) {
                System.out.println("钱不够 取不了");
                return;
            }
            System.out.println(this.getName() + "取了" + drawing + "万");
            account.money = account.money - drawing;
            System.out.println("余额还有" + account.money);
        }

    }
}