死信队列，让订单超时的时候有更高的可用性

死信队列

一 、队列的创建和绑定

二、消费者消费，消费失败之后的逻辑

@Component
@Log4j2
@RabbitListener(queues = REAL_DEAD_QUEUE)
public class PayOrderConsumer {
          
   
    @Resource
    OrderMapper orderMapper;
    @Resource
    RabbitTemplate rabbitTemplate;
    @RabbitHandler
    public void receiveDeadMsg(String msg, Channel channel, Message message) throws IOException {
          
   
        JSONObject msgJson = JSON.parseObject(msg);
        int count = Integer.parseInt(msgJson.getString("count"));
        Order order=null;
        try {
          
   
            log.info("接收到消息:{}",msg);
            //业务逻辑
            ....
            channel.basicAck(message.getMessageProperties().getDeliveryTag(), Boolean.FALSE);
        }catch (Exception e){
          
   
            if (count>2){
          
   
                log.info("重试次数超过三次失败的消息:{}",msg)
                //发生异常三次重试都失败的时候的业务逻辑
                ....
                channel.basicAck(message.getMessageProperties().getDeliveryTag(), Boolean.FALSE);
                throw e;
            }else {
          
   
            	//消费消息失败的时候的逻辑
                log.error("消息{}即将再次返回队列处理...",msg);
                msgJson.put("count",count+1); //计数器
                rabbitTemplate.convertAndSend(NORMAL_EXCHANGE, NORMAL_ROUTING_KEY, msgJson.toString(), new MessagePostProcessor() {
          
   
                    @Override
                    public Message postProcessMessage(Message message) throws AmqpException {
          
   
                        MessageProperties messageProperties = message.getMessageProperties();
                        //设置过期时间TTL
                        messageProperties.setExpiration(String.valueOf(EXPIRE));
                        return message;
                    }
                });
            }
            channel.basicAck(message.getMessageProperties().getDeliveryTag(), Boolean.FALSE);
        }
    }

}

三、发送消息

JSONObject jsonObject = new JSONObject();
        jsonObject.put("msg",orderNumber);
        jsonObject.put("count",0);
        rabbitTemplate.convertAndSend(PayOrderRabbitConfig.NORMAL_EXCHANGE,PayOrderRabbitConfig.NORMAL_ROUTING_KEY,jsonObject);
        log.info("生成订单{}成功",orderNumber);