下单流程解耦新方案 - 你知道 Spring 事件监听机制吗

// 1. 自定义订单事件public class OrderEvent extends ApplicationEvent {...}// 2. 定义订单监听器@Componentpublic class OrderListener implements ApplicationListener<OrderEvent> {    @Override    public void onApplicationEvent(OrderEvent event) {    // 生成订单、删除购物车、扣减库存    ...    }}// 3. 通过applicationEventPublisher发布事件@Resourceprivate ApplicationEventPublisher applicationEventPublisher;private void saveOrder(MallUserVO mallUserVO, Long couponUserId, List<ShopCatVO> shopcatVOList, String orderNo) {    // 订单检查    ...    // 生成订单号    String orderNo = NumberUtil.genOrderNo();    // 发布订单事件，在事件监听中处理下单逻辑    applicationEventPublisher.publishEvent(new OrderEvent(orderNo, mallUserVO, couponUserId, shopcatVOList));    // 所有操作成功后，将订单号返回    return orderNo;    ...}

/** * 系统启动时執行 */@Componentpublic class SpringBeanStartupRunner implements ApplicationRunner {
    @Override    public void run(ApplicationArguments args) throws Exception {        // 设置spring默认的事件监听为异步执行        SimpleApplicationEventMulticaster multicaster = SpringContextUtil.getBean(SimpleApplicationEventMulticaster.class);        ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(                5,                10,                60L, TimeUnit.MILLISECONDS,                new LinkedBlockingQueue<>(500),                new CustomizableThreadFactory("newbee—event-task"),                new ThreadPoolExecutor.CallerRunsPolicy()        );        multicaster.setTaskExecutor(threadPoolExecutor);    }}