synchronized代码块使用练习

模拟两个线程同时取钱的过程，使用同步代码块防止多取

package com.hspedu;
 
/**
 * @author: guorui fu
 * @versiion: 1.0
 */
public class Homework02 {
    public static void main(String[] args) {
        Withdraw withdraw = new Withdraw();
        Thread thread1 = new Thread(withdraw);
        thread1.setName("t1");
        Thread thread2 = new Thread(withdraw);
        thread2.setName("t2");
        thread2.start();
        thread1.start();
    }
}
 
class Withdraw implements Runnable {
    private int sum = 10000;
 
    @Override
    public void run() {
 
        while (true) {
            synchronized (this) {
                if (sum <= 0) {
 
                    System.out.println(Thread.currentThread().getName() + " 尝试取钱，但余额不足。。。");
                    break;
                }
 
                sum -= 1000;
                System.out.println(Thread.currentThread().getName() + "取出1000,余额：" + sum);
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
 
    }
}