介绍死信队列：没有被及时消费的消息存放的队列，消息没有被及时消费有以下几点原因：1.有消息被拒绝（basic.reject/ basic.nack）并且requeue=false2.队列达到最大长度3.消息TTL过期
场景
1.小时进入初始队列，等待30分钟后进入5分钟队列2.消息等待5分钟后进入执行队列3.执行失败后重新回到5分钟队列4.失败5次后，消息进入2小时队列5.消息等待2小时进入执行队列6.失败5次后，将消息丢弃或做其他处理
使用安装MQ使用docker方式安装,选择带mangement的版本
docker pull rabbitmq:managementdocker run -d -p 5672:5672 -p 15672:15672 --name rabbitmq rabbitmq:management访问 localhost: 15672,默认账号密码guest/guest
项目配置（1）创建springboot项目（2）在application.properties配置文件中配置mq连接信息
spring.rabbitmq.host=localhostspring.rabbitmq.port=5672spring.rabbitmq.username=guestspring.rabbitmq.password=guest（3）队列配置
package com.df.ps.mq;import org.springframework.amqp.core.Binding;import org.springframework.amqp.core.BindingBuilder;import org.springframework.amqp.core.Queue;import org.springframework.amqp.core.TopicExchange;import org.springframework.amqp.rabbit.connection.ConnectionFactory;import org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer;import org.springframework.amqp.rabbit.listener.adapter.MessageListenerAdapter;import org.springframework.beans.factory.annotation.Autowire;import org.springframework.beans.factory.annotation.Value;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import java.util.HashMap;import java.util.Map;@Configurationpublic class MqConfig { //time @Value("${spring.df.buffered.min:120}") private int springdfBufferedTime; @Value("${spring.df.high-buffered.min:5}") private int springdfHighBufferedTime; @Value("${spring.df.low-buffered.min:120}") private int springdfLowBufferedTime; // 30min Buffered Queue @Value("${spring.df.queue:spring-df-buffered-queue}") private String springdfBufferedQueue; @Value("${spring.df.topic:spring-df-buffered-topic}") private String springdfBufferedTopic; @Value("${spring.df.route:spring-df-buffered-route}") private String springdfBufferedRouteKey; // 5M Buffered Queue @Value("${spring.df.high-buffered.queue:spring-df-high-buffered-queue}") private String springdfHighBufferedQueue; @Value("${spring.df.high-buffered.topic:spring-df-high-buffered-topic}") private String springdfHighBufferedTopic; @Value("${spring.df.high-buffered.route:spring-df-high-buffered-route}") private String springdfHighBufferedRouteKey; // High Queue @Value("${spring.df.high.queue:spring-df-high-queue}") private String springdfHighQueue; @Value("${spring.df.high.topic:spring-df-high-topic}") private String springdfHighTopic; @Value("${spring.df.high.route:spring-df-high-route}") private String springdfHighRouteKey; // 2H Low Buffered Queue @Value("${spring.df.low-buffered.queue:spring-df-low-buffered-queue}") private String springdfLowBufferedQueue; @Value("${spring.df.low-buffered.topic:spring-df-low-buffered-topic}") private String springdfLowBufferedTopic; @Value("${spring.df.low-buffered.route:spring-df-low-buffered-route}") private String springdfLowBufferedRouteKey; // Low Queue @Value("${spring.df.low.queue:spring-df-low-queue}") private String springdfLowQueue; @Value("${spring.df.low.topic:spring-df-low-topic}") private String springdfLowTopic; @Value("${spring.df.low.route:spring-df-low-route}") private String springdfLowRouteKey; @Bean(autowire = Autowire.BY_NAME, value = "springdfBufferedQueue") Queue springdfBufferedQueue() { int bufferedTime = 1000 * 60 * springdfBufferedTime; return createBufferedQueue(springdfBufferedQueue, springdfHighBufferedTopic, springdfHighBufferedRouteKey, bufferedTime); } @Bean(autowire = Autowire.BY_NAME, value = "springdfHighBufferedQueue") Queue springdfHighBufferedQueue() { int highBufferedTime = 1000 * 60 * springdfHighBufferedTime; return createBufferedQueue(springdfHighBufferedQueue, springdfHighTopic, springdfHighRouteKey, highBufferedTime); } @Bean(autowire = Autowire.BY_NAME, value = "springdfHighQueue") Queue springdfHighQueue() { return new Queue(springdfHighQueue, true); } @Bean(autowire = Autowire.BY_NAME, value = "springdfLowBufferedQueue") Queue springdfLowBufferedQueue() { int lowBufferedTime = 1000 * 60 * springdfLowBufferedTime; return createBufferedQueue(springdfLowBufferedQueue, springdfLowTopic, springdfLowRouteKey, lowBufferedTime); } @Bean(autowire = Autowire.BY_NAME, value = "springdfLowQueue") Queue springdfLowQueue() { return new Queue(springdfLowQueue, true); } @Bean(autowire = Autowire.BY_NAME, value = "springdfBufferedTopic") TopicExchange springdfBufferedTopic() { return new TopicExchange(springdfBufferedTopic); } @Bean Binding springBuffereddf(Queue springdfBufferedQueue, TopicExchange springdfBufferedTopic) { return BindingBuilder.bind(springdfBufferedQueue).to(springdfBufferedTopic).with(springdfBufferedRouteKey); } @Bean(autowire = Autowire.BY_NAME, value = "springdfHighBufferedTopic") TopicExchange springdfHighBufferedTopic() { return new TopicExchange(springdfHighBufferedTopic); } @Bean Binding springHighBuffereddf(Queue springdfHighBufferedQueue, TopicExchange springdfHighBufferedTopic) { return BindingBuilder.bind(springdfHighBufferedQueue).to(springdfHighBufferedTopic).with(springdfHighBufferedRouteKey); } @Bean(autowire = Autowire.BY_NAME, value = "springdfHighTopic") TopicExchange springdfHighTopic() { return new TopicExchange(springdfHighTopic); } @Bean Binding springHighdf(Queue springdfHighQueue, TopicExchange springdfHighTopic) { return BindingBuilder.bind(springdfHighQueue).to(springdfHighTopic).with(springdfHighRouteKey); } @Bean(autowire = Autowire.BY_NAME, value = "springdfLowBufferedTopic") TopicExchange springdfLowBufferedTopic() { return new TopicExchange(springdfLowBufferedTopic); } @Bean Binding springLowBuffereddf(Queue springdfLowBufferedQueue, TopicExchange springdfLowBufferedTopic) { return BindingBuilder.bind(springdfLowBufferedQueue).to(springdfLowBufferedTopic).with(springdfLowBufferedRouteKey); } @Bean(autowire = Autowire.BY_NAME, value = "springdfLowTopic") TopicExchange springdfLowTopic() { return new TopicExchange(springdfLowTopic); } @Bean Binding springLowdf(Queue springdfLowQueue, TopicExchange springdfLowTopic) { return BindingBuilder.bind(springdfLowQueue).to(springdfLowTopic).with(springdfLowRouteKey); } @Bean SimpleMessageListenerContainer container(ConnectionFactory connectionFactory, MessageListenerAdapter listenerAdapter) { SimpleMessageListenerContainer container = new SimpleMessageListenerContainer(); container.setConnectionFactory(connectionFactory); container.setQueueNames(springdfHighQueue, springdfLowQueue); container.setMessageListener(listenerAdapter); return container; } @Bean MessageListenerAdapter listenerAdapter(IntegrationReceiver receiver) { MessageListenerAdapter adapter = new MessageListenerAdapter(receiver); adapter.setDefaultListenerMethod("receive"); Map<String, String> queueOrTagToMethodName = new HashMap<>(); queueOrTagToMethodName.put(springdfHighQueue, "springdfHighReceive"); queueOrTagToMethodName.put(springdfLowQueue, "springdfLowReceive"); adapter.setQueueOrTagToMethodName(queueOrTagToMethodName); return adapter; } private Queue createBufferedQueue(String queueName, String topic, String routeKey, int bufferedTime) { Map<String, Object> args = new HashMap<>(); args.put("x-dead-letter-exchange", topic); args.put("x-dead-letter-routing-key", routeKey); args.put("x-message-ttl", bufferedTime); // 是否持久化 boolean durable = true; // 仅创建者可以使用的私有队列，断开后自动删除 boolean exclusive = false; // 当所有消费客户端连接断开后，是否自动删除队列 boolean autoDelete = false; return new Queue(queueName, durable, exclusive, autoDelete, args); }}消费者配置package com.df.ps.mq;import com.fasterxml.jackson.databind.ObjectMapper;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.amqp.rabbit.core.RabbitTemplate;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.beans.factory.annotation.Value;import java.util.Map;public class MqReceiver { private static Logger logger = LoggerFactory.getLogger(MqReceiver.class); @Value("${high-retry:5}") private int highRetry; @Value("${low-retry:5}") private int lowRetry; @Value("${spring.df.high-buffered.topic:spring-df-high-buffered-topic}") private String springdfHighBufferedTopic; @Value("${spring.df.high-buffered.route:spring-df-high-buffered-route}") private String springdfHighBufferedRouteKey; @Value("${spring.df.low-buffered.topic:spring-df-low-buffered-topic}") private String springdfLowBufferedTopic; @Value("${spring.df.low-buffered.route:spring-df-low-buffered-route}") private String springdfLowBufferedRouteKey; private final RabbitTemplate rabbitTemplate; @Autowired public MqReceiver(RabbitTemplate rabbitTemplate) { this.rabbitTemplate = rabbitTemplate; } public void receive(Object message) { if (logger.isInfoEnabled()) { logger.info("default receiver: " + message); } } /** * 消息从初始队列进入5分钟的高速缓冲队列 * @param message */ public void highReceiver(Object message){ ObjectMapper mapper = new ObjectMapper(); Map msg = mapper.convertValue(message, Map.class); try{ logger.info("这里做消息处理..."); }catch (Exception e){ int times = msg.get("times") == null ? 0 : (int) msg.get("times"); if (times < highRetry) { msg.put("times", times + 1); rabbitTemplate.convertAndSend(springdfHighBufferedTopic,springdfHighBufferedRouteKey,message); } else { msg.put("times", 0); rabbitTemplate.convertAndSend(springdfLowBufferedTopic,springdfLowBufferedRouteKey,message); } } } /** * 消息从5分钟缓冲队列进入2小时缓冲队列 * @param message */ public void lowReceiver(Object message){ ObjectMapper mapper = new ObjectMapper(); Map msg = mapper.convertValue(message, Map.class); try { logger.info("这里做消息处理..."); }catch (Exception e){ int times = msg.get("times") == null ? 0 : (int) msg.get("times"); if (times < lowRetry) { rabbitTemplate.convertAndSend(springdfLowBufferedTopic,springdfLowBufferedRouteKey,message); }else{ logger.info("消息无法被消费..."); } } }}