• 生产者完成创建订单和扣减库存之后，发送消息到延迟队列。

// 3.清理购物车商品
        cartClient.deleteCartItemByIds(itemIds);
        // cartService.removeByItemIds(itemIds);

        // 4.扣减库存
        try {
            itemClient.deductStock(detailDTOS);
            //itemService.deductStock(detailDTOS);
        } catch (Exception e) {
            throw new RuntimeException("库存不足！");
        }

        // 5.TODO发送延迟消息，检查用户是否已经支付完成
        rabbitTemplate.convertAndSend(MQConstants.DELAY_EXCHANGE_NAME,
                MQConstants.DELAY_ORDER_KEY,
                order.getId(),
                message -> {
                    message.getMessageProperties().setDelay(10000);
                    return message;
                });

• 消费者监听消息，先查订单状态，没支付在查支付信息。

@Slf4j
@Component
@AllArgsConstructor
public class OrderDelayMessageListener {

    private final IOrderService orderService;
    private final PayClient payClient;

    @RabbitListener(bindings = @QueueBinding(
            value = @Queue(name = MQConstants.DELAY_ORDER_QUEUE_NAME),
            exchange = @Exchange(name = MQConstants.DELAY_EXCHANGE_NAME, delayed = "true"),
            key = MQConstants.DELAY_ORDER_KEY
    ))
    public void listenOrderDelayMessage(Long orderId) {
        // 1.查询订单状态
        Order order = orderService.getById(orderId);

        // 2.检测订单状态，判断是否已支付
        if(order == null || order.getStatus()!=1) {
            log.info("delayMQ：用户已支付订单【{}】",orderId);
            return;
        }

        // 3.未支付，查询订单流水
        PayOrderDTO payOrder = payClient.queryPayOrderByBizOrderNo(orderId);

        // 4.判断是否支付
        if (payOrder == null || payOrder.getStatus() == 3) {
            // 4.1 已支付，标记订单状态已支付
            orderService.markOrderPaySuccess(orderId);
            log.info("delayMQ：已更新订单【{}】",orderId);
        } else {
            // 4.2 未支付，取消订单，恢复库存
            orderService.cancelOrder(orderId);
            log.info("delayMQ：已取消订单【{}】",orderId);
        }
    }
}