设计一个高铁购票的应用程序，设车站初始有10张票，用线程模拟3个用户购票，每次购票1张，售完为止。使用多线程的同步控制编程。
public class CheZhan {
public static void main(String[] args){
Customer customer = new Customer();
Thread thread1 = new Thread(customer, "1号乘客：");
Thread thread2 = new Thread(customer, "2号乘客：");
Thread thread3 = new Thread(customer, "3号乘客：");
thread1.start();
thread2.start();
thread3.start();
}
}
class Customer implements Runnable{
private int tickets = 10;
@Override
public void run() {
while (tickets > 0){
synchronized (Customer.class){
if (tickets > 0){
try {
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
tickets--;
} else {
System.out.println("当日票次已售完！！！");
System.exit(0);
}
}
System.out.println(Thread.currentThread().getName() + "购票一张，剩余票数：" + tickets);
}
}
}
