如何将普通队列异常消息路由到死信队列

在RabbitMQ中，我们经常需要处理异常消息，特别是当消息处理失败时。一个常见的用例是将异常消息路由到死信队列，以便稍后重新处理或进一步分析。在本篇博客中，我们将演示如何配置RabbitMQ和Spring Boot，以便将普通队列中的异常消息自动路由到死信队列。

步骤1：创建Spring Boot项目

首先，创建一个Spring Boot项目并添加以下依赖：

<dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-amqp</artifactId></dependency><dependency><groupId>cn.hutool</groupId><artifactId>hutool-all</artifactId><version>5.8.0</version></dependency>
</dependencies>

步骤2：配置RabbitMQ和队列

在`application.yml文件中，配置RabbitMQ连接信息：

spring:#给项目来个名字application:name: rabbitmq-provider#配置rabbitMq 服务器rabbitmq:host: 127.0.0.1port: 5672username: rootpassword: 123456#虚拟host 可以不设置,使用server默认hostvirtual-host: /cdn#确认消息已发送到交换机(Exchange)#确认消息已发送到队列(Queue)publisher-returns: truelistener:simple:acknowledge-mode: autoretry:#enabled：开启失败重试enabled: true#第一次重试的间隔时长initial-interval: 1000ms#最长重试间隔，超过这个间隔将不再重试max-interval: 300000ms#下次重试间隔的倍数，此处是2即下次重试间隔是上次的2倍multiplier: 2max-attempts: 4default-requeue-rejected: false  # 达到重试次数进入死信队列publisher-confirm-type: none

然后，创建一个Spring组件，它将包括配置RabbitMQ队列和消息监听器：

import org.springframework.amqp.core.*;
import org.springframework.amqp.rabbit.annotation.RabbitListener;
import org.springframework.amqp.rabbit.core.RabbitTemplate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import cn.hutool.core.util.RandomUtil;@RestController
public class ExceptionToDead {@AutowiredRabbitTemplate rabbitTemplate;@Beanpublic Queue normalQueue() {return QueueBuilder.durable("my-normal-queue").withArgument("x-dead-letter-exchange", "my-dead-letter-exchange").withArgument("x-dead-letter-routing-key", "my-dead-letter-routing-key").build();}@Beanpublic DirectExchange normalExchange() {return new DirectExchange("my-normal-exchange");}@Beanpublic Binding normalBinding(Queue normalQueue, DirectExchange normalExchange) {return BindingBuilder.bind(normalQueue).to(normalExchange).with("my-normal-routing-key");}@Beanpublic DirectExchange deadLetterExchange() {return new DirectExchange("my-dead-letter-exchange");}@Beanpublic Queue deadLetterQueue() {return QueueBuilder.durable("my-dead-letter-queue").build();}@Beanpublic Binding deadLetterBinding(Queue deadLetterQueue, DirectExchange deadLetterExchange) {return BindingBuilder.bind(deadLetterQueue).to(deadLetterExchange).with("my-dead-letter-routing-key");}@RabbitListener(queues = "my-normal-queue")public void receiveFromNormalQueue(Integer message) {System.out.println("正常队列收到消息: " + message);if (message % 2 == 0) {int a = 1 / 0; // 引发异常}}@RabbitListener(queues = "my-dead-letter-queue")public void receiveFromDeadLetterQueue(Integer message) {System.out.println("死信队列收到消息: " + message);}@GetMapping("send")public void send() {int number = RandomUtil.randomInt(0, 100);rabbitTemplate.convertAndSend("my-normal-exchange", "my-normal-routing-key", number);}@GetMapping("b")public void b() {int number = RandomUtil.randomInt(0, 100);rabbitTemplate.convertAndSend("simple-key", number);}
}

在这段代码中，我们创建了一个名为my-normal-queue的队列，它将异常消息路由到my-dead-letter-exchange交换机，然后再路由到my-dead-letter-queue队列。我们还创建了相应的交换机和绑定。

注意：自动确认的时候，达到重试次数之后就会路由到绑定的死信，否则消息会丢失

手动确认的时候，消费时候在需要的位置channel.basicNack(message.getMessageProperties().getDeliveryTag(),false,false); 消息才会路由到死信，否则消息会积压