@Component
public class OrderJob {
@Autowired
private OrderService orderService;
/**
* 使用定时任务关闭超期未支付订单，会存在的弊端：
* 1. 会有时间差，程序不严谨
* 10:39下单，11:00检查不足1小时，12:00检查，超过1小时多余39分钟
* 2. 不支持集群
* 单机没毛病，使用集群后，就会有多个定时任务
* 解决方案：只使用一台计算机节点，单独用来运行所有的定时任务
* 3. 会对数据库全表搜索，及其影响数据库性能：select * from order where orderStatus = 10;
* 定时任务，仅仅只适用于小型轻量级项目，传统项目
*
* 后续课程会涉及到消息队列：MQ-> RabbitMQ, RocketMQ, Kafka, ZeroMQ...
* 延时任务（队列）
* 10:12分下单的，未付款（10）状态，11:12分检查，如果当前状态还是10，则直接关闭订单即可
*/
// @Scheduled(cron = "0/3 * * * * ?")
// @Scheduled(cron = "0 0 0/1 * * ?")
public void autoCloseOrder() {
orderService.closeOrder();
System.out.println("执行定时任务，当前时间为："
+ DateUtil.getCurrentDateString(DateUtil.DATETIME_PATTERN));
}
}
/**
* A cron-like expression, extending the usual UN*X definition to include triggers
* on the second as well as minute, hour, day of month, month and day of week.
* <p>E.g. {@code "0 * * * * MON-FRI"} means once per minute on weekdays
* (at the top of the minute - the 0th second).
* <p>The special value {@link #CRON_DISABLED "-"} indicates a disabled cron trigger,
* primarily meant for externally specified values resolved by a ${...} placeholder.
* @return an expression that can be parsed to a cron schedule
* @see org.springframework.scheduling.support.CronSequenceGenerator
*/
String cron() default "";
@EnableScheduling // 开启定时任务
