RabbitMQ深度探索：消息幂等性问题

1. 我们需要将日志存放起来，后期通过定时任务或者人工补偿形式
2. 如果是重试多次还是失败消息，需要重新发布消费者版本实现消费
3. 可以使用死信队列

1. 幂等性：保证数据唯一

1. 当消费者业务逻辑代码中抛出异常自动实现重试(默认是无数次重试)
2. 应该对 RabbitMQ 重试次数实现限制，比如最多重试 5 次，每次间隔 30 秒
3. 重试多次还是失败的情况下，存放到死信队列或者存放到数据库表中记录后期人工补偿

1. 如果消费者处理消息时，因为代码原因抛出异常是需要重新发布版本才能解决，就不要重试
2. 存放到死信队列或者是数据库记录、后期人工实现补偿

spring:rabbitmq:####连接地址host: 127.0.0.1####端口号port: 5672####账号username: guest####密码password: guest### 地址virtual-host: boyatopVirtualHostlistener:simple:retry:#开启消费者进行重试(程序异常的情况)enabled: true#最大重试次数max-attempts: 5#重试间隔时间initial-interval: 3000#手动确认机制acknowledge-mode: manualdatasource:url: jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8username: rootpassword: rootdriver-class-name: com.mysql.jdbc.Driverboyatop:#备胎交换机dlx:exchange: boyatop_dlx_exchangequeue: boyatop_dlx_queueroutingKey: dlx#普通交换机order:exchange: boyatop_order_exchangequeue: boyatop_order_queueroutingKey: order

@Component
public class IdempotentExchangeConfig {//交换机@Value("${boyatop.order.exchange}")private  String order_exchange;//普通队列@Value("${boyatop.order.queue}")private String order_queue;//普通队列的 key@Value("${boyatop.order.routingKey}")private String order_rotingKey;//死信交换机@Value("${boyatop.dlx.exchange}")private String dlx_exchange;//死信队列@Value("${boyatop.dlx.queue}")private String dlx_queue;//死信队列的 key@Value("${boyatop.dlx.routingKey}")private String dlx_routingKey;//定义死信交换机@Beanpublic DirectExchange dlxExchange(){return new DirectExchange(dlx_exchange);}//定义死信队列@Beanpublic Queue dlxQueue(){return new Queue(dlx_queue);}//定义普通交换机@Beanpublic DirectExchange orderExchange(){return new DirectExchange(order_exchange);}//定义普通队列@Beanpublic Queue orderQueue(){//订单队列绑定死信交换机Map<String,Object> arguments = new HashMap<>(2);arguments.put("x-dead-letter-exchange",dlx_exchange);arguments.put("x-dead-letter-routing-key",dlx_routingKey);return new Queue(order_queue,true,false,false,arguments);
//        return QueueBuilder.durable(order_queue).withArguments(arguments).build();}//订单队列绑定交换机@Beanpublic Binding bindingOrderExchange(DirectExchange orderExchange, Queue orderQueue){return BindingBuilder.bind(orderQueue).to(orderExchange).with(order_rotingKey);}//死信队列绑定交换机@Beanpublic Binding bindingDlxExchange(DirectExchange dlxExchange, Queue dlxQueue){return BindingBuilder.bind(dlxQueue).to(dlxExchange).with(dlx_routingKey);}}

@Data
@NoArgsConstructor
public class OrderEntity implements Serializable {private Integer id;private String orderName;private String orderId;public OrderEntity(String orderName, String orderId) {this.orderName = orderName;this.orderId = orderId;}
}

public interface OrderMapper {@Insert("INSERT into order_entity value (null,#{orderName},#{orderId})")int addOrder(OrderEntity orderEntity);@Select("select * from order_entity where order_id = #{orderId} ")OrderEntity getOrder(String orderId);
}

@Component
@Slf4j
public class OrderProducer {@Autowiredprivate RabbitTemplate rabbitTemplate;@Value("${boyatop.order.exchange}")private  String order_exchange;//普通队列的 key@Value("${boyatop.order.routingKey}")private String order_rotingKey;public void sendMsg(String orderName,String orderId){OrderEntity orderEntity = new OrderEntity(orderName,orderId);rabbitTemplate.convertAndSend(order_exchange,order_rotingKey,orderEntity,message -> {message.getMessageProperties().setExpiration("5000");return message;});}
}

@Component
@Slf4j
@RabbitListener(queues = "boyatop_order_queue")
public class OrderConsumer {@Autowiredprivate OrderMapper orderMapper;@RabbitHandlerpublic void process(OrderEntity orderEntity, Message message, Channel channel){try{String orderId = orderEntity.getOrderId();if(StringUtils.isEmpty(orderId)){return;}OrderEntity dbOrderEntity = orderMapper.getOrder(orderId);if(dbOrderEntity != null){//出现异常,消息拒收,进入死信队列人为处理channel.basicNack(message.getMessageProperties().getDeliveryTag(),false,false);}int result = orderMapper.addOrder(orderEntity);//出现异常int i = 1 / 0;channel.basicAck(message.getMessageProperties().getDeliveryTag(),false);System.out.println("监听内容:" + orderEntity);}catch (Exception e){// 记录该消息日志形式  存放数据库db中、后期通过定时任务实现消息补偿、人工实现补偿//将该消息存放到死信队列中，单独写一个死信消费者实现消费。}}
}