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RabbitMQ

一、RabbitMQ介绍

1.1 现存问题

• • 服务异步调用： 服务A如何保证异步请求一定能被服务B接收到并处理
    
• • 削峰: 海量请求，如何实现削峰的效果，将请求全部放到一个队列中，慢慢的消费，这个队列怎么实现？

• • 服务解耦： 如何尽量的降低服务之间的耦合问题，如果在订单与积分和商家服务解构，需要一个队列，而这个队列依然需要实现上述两个情况功能。

一、RabbitMQ介绍

RabbitMQ是实现了高级消息队列协议（AMQP）的开源消息代理软件（亦称面向消息的中间件）。RabbitMQ服务器是用Erlang语言编写的，而集群和故障转移是构建在开放电信平台框架上的。所有主要的编程语言均有与代理接口通讯的客户端库。

AMQP协议：

Erlang：

Erlang在1991年由爱立信公司向用户推出了第一个版本，经过不断的改进完善和发展，在1996年爱立信又为所有的Erlang用户提供了一个非常实用且稳定的OTP软件库并在1998年发布了第一个开源版本。Erlang同时支持的操作系统有linux,windows,unix等，可以说适用于主流的操作系统上，尤其是它支持多核的特性非常适合多核CPU，而分布式特性也可以很好融合各种分布式集群。

二、RabbitMQ安装

docker-compose.yml

version: “3.1”
services:
rabbitmq:
image: daocloud.io/library/rabbitmq:3.8.5
container_name: rabbitmq
restart: always
volumes:
- ./data/:/var/lib/rabbitmq/
ports:
- 5672:5672
- 15672:15672

docker-compose.yml文件内容：

镜像拉取完成后，直接在linux 内部执行： curl localhost:5672

执行后能够显示AMQP 字样的内容就说明执行成功了

执行 docker exec -it rabbitmq bash 命令 进入容器内部
cd opt/rabbitmq/ 目录下

执行cd plugins/sbin 命令进入目录下， 执行 ./rabbitmq-plugins enable rabbitmq_managent命令 启动rabbitmq 图形化界面

访问15672 端口，默认的账号密码是guest/guest

三、RabbitMQ架构

四、RabbitMQ通信方式

4.1 RabbitMQ提供的通讯方式

• Hello World :为了入门操作
• Work queues ： 一个队列被多个消费者消费
• Publish/Subscribe：手动创建Exchange（FANOUT）
• Routing： 手动创建Exchange（DIRECT）
• Topics ： 手动创建Exchange（TOPIC）
• RPC： RPC方式
• Publisher Confirms

4.2 Helloworld 方式

//工具类
public class RabbitMQConnectionUtil {public static final String RABBITMQ_HOST ="172.16.177.133";public static final int RABBITMQ_POST =5672;public static final String RABBITMQ_USERNAME ="guest";public static final String RABBITMQ_PASSWORD ="guest";public static final String RABBITMQ_VIRTUAL_HOST ="/";/*** 构建RabbitMQ的连接对象* @return*/public static Connection getConnection() throws Exception{//1.创建connection    工厂对象ConnectionFactory connectionFactory = new ConnectionFactory();connectionFactory.setHost(RABBITMQ_HOST);connectionFactory.setPort(RABBITMQ_POST);connectionFactory.setUsername(RABBITMQ_USERNAME);connectionFactory.setPassword(RABBITMQ_PASSWORD);connectionFactory.setVirtualHost(RABBITMQ_VIRTUAL_HOST);//2.设置RabbitMQ的连接信息Connection connection = connectionFactory.newConnection();//3. 返回连接对象return connection;}
//生产者@Testpublic void consume() throws Exception {//1.获取连接对象Connection connection = RabbitMQConnectionUtil.getConnection();//2.创建Channel 通道Channel channel = connection.createChannel();//3.构建队列channel.queueDeclare(Publisher.QUEUE_NAME,false,false,false,null);//4. 监听消息DefaultConsumer callback =new DefaultConsumer(channel){@Overridepublic void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {System.out.println("消息者获取消息"+new String(body,"UTF-8"));}};channel.basicConsume(Publisher.QUEUE_NAME,true,callback);System.out.println("开始监听");System.in.read();}//消费者@Testpublic void publish() throws Exception {//1.获取连接对象Connection connection = RabbitMQConnectionUtil.getConnection();//2.创建Channel 通道Channel channel = connection.createChannel();//3.构建队列channel.queueDeclare(QUEUE_NAME,false,false,false,null);//4. 发布消息String message="hello word!";channel.basicPublish("",QUEUE_NAME,null,message.getBytes());System.out.println("消息发送成功");System.in.read();}

4.2Work queues

一个队列中的消息，只会被一个消费者成功的消费，默认情况下，RabbitMQ的队列会将消息以轮询的方式交给不同的消费者消费，消费者拿到消息后，需要给RabbitMQ一个ack，RabbitMQ认为消费者已经拿到消息了

//消费者@Testpublic void consume() throws Exception {//1.获取连接对象Connection connection = RabbitMQConnectionUtil.getConnection();//2.创建Channel 通道Channel channel = connection.createChannel();//3.构建队列channel.queueDeclare(Publisher.QUEUE_NAME,false,false,false,null);//3.1 设置消息的控制,一次拿几个消息
//#2        channel.basicQos(1);//4. 监听消息DefaultConsumer callback =new DefaultConsumer(channel){@Overridepublic void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {try {//模拟业务执行时间Thread.sleep(100);} catch (InterruptedException e) {e.printStackTrace();}System.out.println("消息者获取消息"+new String(body,"UTF-8"));
//#1				channel.basicAck(envelope.getDeliveryTag(),false);}};channel.basicConsume(Publisher.QUEUE_NAME,true,callback);
//#1		channel.basicConsume(Publisher.QUEUE_NAME,false,callback);System.out.println("开始监听");System.in.read();//消费者2@Testpublic void consume2() throws Exception {//1.获取连接对象Connection connection = RabbitMQConnectionUtil.getConnection();//2.创建Channel 通道Channel channel = connection.createChannel();//3.构建队列channel.queueDeclare(Publisher.QUEUE_NAME,false,false,false,null);//3.1 设置消息的控制,一次拿几个消息
//#2        channel.basicQos(1);//4. 监听消息 DefaultConsumer callback =new DefaultConsumer(channel){@Overridepublic void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {try {//模拟业务执行时间Thread.sleep(1000);} catch (InterruptedException e) {e.printStackTrace();}System.out.println("消息者获取消息"+new String(body,"UTF-8"));//basicAck(标识,是否批量操作)
//#1				channel.basicAck(envelope.getDeliveryTag(),false);}};channel.basicConsume(Publisher.QUEUE_NAME,true,callback);
//#1		channel.basicConsume(Publisher.QUEUE_NAME,false,callback);System.out.println("开始监听");System.in.read();}
//生产者public static final String QUEUE_NAME="work";@Testpublic void publish() throws Exception {//1.获取连接对象Connection connection = RabbitMQConnectionUtil.getConnection();//2.创建Channel 通道Channel channel = connection.createChannel();//3.构建队列channel.queueDeclare(QUEUE_NAME,false,false,false,null);//4. 发布消息for (int i=0;i<10;i++){String message="hello word!"+i;channel.basicPublish("",QUEUE_NAME,null,message.getBytes());}System.out.println("消息发送成功");System.in.read();}

当两台消费者的消费能力不相同的时候，为了提高效率，就不能以轮询的方式进行分发，而是以消费者消费完成后手动传递ack 的方式进行下一个消息的分发，将== #1 #2 的代码 ==打开即可
操作步骤：

• 操作#1 让消费者关闭自动ack，并且设置消息的流控，最终实现消费者可以尽可能去多消费消息
• 操作#2 设置每次拿几个消息

4.3 Publish/Subscribe

自行创建路由器，并绑定队列

如何构建一个自定义交换机，并指定类型是FANOUT，让交换机和多个Queue绑定到一起

//生产者 
public static final String EXCHANGE_NAME="pubsub";public static final String QUEUE_NAME1="pubsub-one";public static final String QUEUE_NAME2="pubsub-two";@Testpublic void pulish() throws Exception {//1.获取连接对象Connection connection = RabbitMQConnectionUtil.getConnection();//2. 构建ChannalChannel channel = connection.createChannel();//3.构建虚拟机, exchange 交换机名称，type 交换机类型【枚举】channel.exchangeDeclare(EXCHANGE_NAME, BuiltinExchangeType.FANOUT);//4. 构建队列channel.queueDeclare(QUEUE_NAME1, false, false, false, null);channel.queueDeclare(QUEUE_NAME2, false, false, false, null);//5. 绑定 交换机 和 队列,使用的是FANOUT类型的交换机，绑定方式是直接绑定 ,routingkey 参数随便写什么都可以，channel.queueBind(QUEUE_NAME1,EXCHANGE_NAME,"");channel.queueBind(QUEUE_NAME2,EXCHANGE_NAME,"");//6.发消息到交换机channel.basicPublish(EXCHANGE_NAME,"",null,"publish/subscribe!".getBytes());System.out.println("消息成功发送");}

4.4 Routing

DIRECT 类型的交换机，在绑定Exchange和Queue时，需要指定好routingKey同时在发送消息的时候，也指定routingkey，只有在routingkey 一致时，才会把指定的消息路由到指定的队列

public static final String EXCHANGE_NAME="routing";public static final String QUEUE_NAME1="routing-one";public static final String QUEUE_NAME2="routing-two";@Testpublic void pulish() throws Exception {//1.获取连接对象Connection connection = RabbitMQConnectionUtil.getConnection();//2. 构建ChannalChannel channel = connection.createChannel();//3.构建虚拟机, exchange 交换机名称，type 交换机类型【枚举】 * 交换机类型 改成 BuiltinExchangeType.DIRECTchannel.exchangeDeclare(EXCHANGE_NAME, BuiltinExchangeType.DIRECT);//4. 构建队列channel.queueDeclare(QUEUE_NAME1, false, false, false, null);channel.queueDeclare(QUEUE_NAME2, false, false, false, null);//5. 绑定 交换机 和 队列,使用的是FANOUT类型的交换机，绑定方式是直接绑定 ,routingkey 参数随便写什么都可以，channel.queueBind(QUEUE_NAME1,EXCHANGE_NAME,"ORANGE");channel.queueBind(QUEUE_NAME2,EXCHANGE_NAME,"BLACK");channel.queueBind(QUEUE_NAME2,EXCHANGE_NAME,"GREEN");//6.发消息到交换机channel.basicPublish(EXCHANGE_NAME,"ORANGE",null,"大橙子!".getBytes());channel.basicPublish(EXCHANGE_NAME,"BLACK",null,"黑布林!".getBytes());channel.basicPublish(EXCHANGE_NAME,"WHITE",null,"小白兔!".getBytes());System.out.println("消息成功发送");}

4.5 Topics

topics 模式支持模糊匹配RoutingKey，就像是sql中的 like子句模糊查询，而路由模式等同于sql中的where子句等值查询

通过模糊路由到队列。该方式的Routing key必须具有固定格式：以 . 间隔的一串单词，比如：quick.orange.rabbit，Routing key 最多不能超过255byte。

交换机和队列的Binding key用通配符来表示，有两种语法：

• * 可以替代一个单词；
• # 可以替代 0 或多个单词；

例如 #.com.#
#可以表示0级或多级。xx.com、com.xx、com、xx.com.xx.xx、xx.xx.com.xx都可以

例如 *.com. *
*表示一级，xx.com.xx 可以 ，com.xx 不可以，前面缺少一级，xx.com.xx.xx不可以，com后面只能有一级xx，最终格式必须是 xx.com.xx

 public static final String EXCHANGE_NAME="topics";public static final String QUEUE_NAME1="topics-one";public static final String QUEUE_NAME2="topics-two";@Testpublic void pulish() throws Exception {//1.获取连接对象Connection connection = RabbitMQConnectionUtil.getConnection();//2. 构建ChannalChannel channel = connection.createChannel();//3.构建虚拟机, exchange 交换机名称，type 交换机类型【枚举】 * 交换机类型 改成 BuiltinExchangeType.TOPICchannel.exchangeDeclare(EXCHANGE_NAME, BuiltinExchangeType.TOPIC);//4. 构建队列channel.queueDeclare(QUEUE_NAME1, false, false, false, null);channel.queueDeclare(QUEUE_NAME2, false, false, false, null);//5. 绑定 交换机 和 队列,// Topic类型的交换机，在和队列绑定时，需要以aaa.bbb.ccc 方式编写routingKey// 其中有两个特殊字符： *(相当于占位符)，# (相当通配符)channel.queueBind(QUEUE_NAME1,EXCHANGE_NAME,"*.orange.*");channel.queueBind(QUEUE_NAME2,EXCHANGE_NAME,"*.*.rabbit");channel.queueBind(QUEUE_NAME2,EXCHANGE_NAME,"lazy.#");//6.发消息到交换机channel.basicPublish(EXCHANGE_NAME,"big.orange.rabbit",null,"大橙子兔子!".getBytes());//匹配1、2channel.basicPublish(EXCHANGE_NAME,"small.while.rabbit",null,"小兔子!".getBytes());//匹配1、2channel.basicPublish(EXCHANGE_NAME,"lazy.dog.dog.dog.dog",null,"懒狗狗狗狗!".getBytes());//匹配 3System.out.println("消息成功发送");}

4.6 RPC (了解)

因为两个服务在交互时，可以尽量做到Client和server的结偶，通过RabbitMQ进行结藕操作
需要让client 发送消息时，携带两个属性，

• replyto告知server将相应信息放到哪个队列
• correlationId告知server 发送相应消息时，需要携带位置标识来告知client响应的消息

public class Publisher {public static final String QUEUE_PUBLISHER = "rpc_publisher";public static final String QUEUE_CONSUMER = "rpc_consumer";@Testpublic void publish() throws Exception {//1.获取连接对象Connection connection = RabbitMQConnectionUtil.getConnection();//2.创建Channel 通道Channel channel = connection.createChannel();//3.构建队列channel.queueDeclare(QUEUE_PUBLISHER,false,false,false,null);channel.queueDeclare(QUEUE_CONSUMER,false,false,false,null);//4. 发布消息String message="hello rpc!";String uuid = UUID.randomUUID().toString();AMQP.BasicProperties prop =new AMQP.BasicProperties().builder().replyTo(QUEUE_CONSUMER).correlationId(uuid).build();channel.basicPublish("",QUEUE_PUBLISHER,prop,message.getBytes());channel.basicConsume(QUEUE_CONSUMER,false,new DefaultConsumer(channel){@Overridepublic void handleDelivery(String consumerTag, Envelope envelope,AMQP.BasicProperties properties,byte[] body) throws IOException {String id = properties.getCorrelationId();if(id!=null && id.equals(uuid)){System.out.println("接收到服务端的响应："+new String(body));}channel.basicAck(envelope.getDeliveryTag(),false);}});System.out.println("消息发送成功");System.in.read();}
}public class Consumer {public static final String QUEUE_PUBLISHER = "rpc_publisher";public static final String QUEUE_CONSUMER = "rpc_consumer";@Testpublic void consume() throws Exception {//1.获取连接对象Connection connection = RabbitMQConnectionUtil.getConnection();//2.创建Channel 通道Channel channel = connection.createChannel();//3.构建队列channel.queueDeclare(QUEUE_PUBLISHER,false,false,false,null);channel.queueDeclare(QUEUE_CONSUMER,false,false,false,null);//4. 监听消息DefaultConsumer callback =new DefaultConsumer(channel){@Overridepublic void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {System.out.println("消息者获取消息"+new String(body,"UTF-8"));String resp = "获取到client发出的请求，这里是响应的信息";String respQueueName = properties.getReplyTo();String uuid = properties.getCorrelationId();AMQP.BasicProperties prop =new AMQP.BasicProperties().builder().correlationId(uuid).build();channel.basicPublish("",respQueueName,prop,resp.getBytes());channel.basicAck(envelope.getDeliveryTag(),false);}};channel.basicConsume(QUEUE_PUBLISHER,false,callback);System.out.println("开始监听");System.in.read();}
}

五、Springboot 操作RabbitMQ

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• 创建项目
• 导入依赖

	<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-amqp</artifactId></dependency>

• 配置rabbitmq信息

spring:rabbitmq:host: 172.16.177.133password: guestusername: guestport: 5672virtual-host: /

配置类声明队列

@Configuration
public class RabbitMQConfig {public static final String EXCHANGE="boot-exchange";public static final String QUEUE="boot-queue";public static final String ROUTING_KEY="*.black.*";@Beanpublic Exchange bootExchange(){return ExchangeBuilder.topicExchange(EXCHANGE).build();}@Beanpublic Queue bootQueue(){return QueueBuilder.durable(QUEUE).build();}@Beanpublic Binding bootBinding(Exchange bootExchange,Queue bootQueue){return BindingBuilder.bind(bootQueue).to(bootExchange).with(ROUTING_KEY).noargs();}
}

生产者配置

@SpringBootTest
class SpringbootRabbitmqApplicationTests {@AutowiredRabbitTemplate rabbitTemplate;@Testvoid contextLoads() {}@Testpublic void publisher(){rabbitTemplate.convertAndSend(RabbitMQConfig.EXCHANGE,"big.black.dog","message");System.out.println("消息发送成功");}@Testpublic void publiWithProps(){rabbitTemplate.convertAndSend(RabbitMQConfig.EXCHANGE, "big.black.dog", "message", new MessagePostProcessor() {@Overridepublic Message postProcessMessage(Message message) throws AmqpException {message.getMessageProperties().setCorrelationId("123");return message;}});System.out.println("消息发送成功2");}
}

消费者配置

@Component
public class ConsumeListener {/**** @param msg* @param channel 前提是配置好spring.rabbitmq.listener.simple.acknowledge-mode: manual #开启手动ack* @param message* @throws IOException*/@RabbitListener(queues = RabbitMQConfig.QUEUE)public void consume(String msg, Channel channel, Message message) throws IOException {System.out.println("队列消息为："+msg);String correlationId = message.getMessageProperties().getCorrelationId();System.out.println("标识为："+correlationId);channel.basicAck(message.getMessageProperties().getDeliveryTag(),false);}
}

• 声明交换机&队列

六、RabbitMQ保证消息可靠性

confirm机制
可以通过confirm效果保证消息一定送达到Exchange，官方提供了三种，选择了对于效率影响最低的异步回调的效果

6.1、 保证消息一定送达到Exchange

使用confirm机制

 public static final String QUEUE_NAME="confirms ";@Testpublic void publish() throws Exception {//1.获取连接对象Connection connection = RabbitMQConnectionUtil.getConnection();//2.创建Channel 通道Channel channel = connection.createChannel();//3.构建队列channel.queueDeclare(QUEUE_NAME,false,false,false,null);//3.1 开启confirms 的异步回调channel.confirmSelect();String message="hello word!";//3.2 设置confirms的异步回调channel.addConfirmListener(new ConfirmListener() {@Overridepublic void handleAck(long deliveryTag, boolean multiple) throws IOException {System.out.println("消息成功发送到Exchange");}@Overridepublic void handleNack(long deliveryTag, boolean multiple) throws IOException {System.out.println("消息没有发送到Exchange，尝试重试，或者保存到数据库做其他补偿操作");}});//3.3 设置return回调，确认消息是否路由到了队列channel.addReturnListener(new ReturnListener() {@Overridepublic void handleReturn(int replyCode, String replyText, String exchange, String routingKey, AMQP.BasicProperties properties, byte[] body) throws IOException {System.out.println("消息没有到指定队列时，做其他的补偿措施！！");}});//3.4、设置消息持久化AMQP.BasicProperties prop =new AMQP.BasicProperties().builder().deliveryMode(2)//消息持久化.build();//4. 发布消息channel.basicPublish("",QUEUE_NAME,true,prop,message.getBytes());System.out.println("消息发送成功");System.in.read();}

6.2、保证消息可以路由到Queue中

使用return 机制
为了保证Exchange上的消息一定可以送达到Queue

//6.2设置return 回调，确认消息是否路由到了Queue
channel.addReturnListener(new ReturnListener() {@Overridepublic void handleReturn(int replyCode, String replyText, String exchange, String routingKey, AMQP.BasicProperties properties, byte[] body) throws IOException {System.out.println("消息没有到指定队列时，做其他的补偿措施！！");}});
//7.在发送消息时，将basicPublish方法参数中的mandatory设置为true，即可开启Return机制，当消息没有路由到队列中时，就会执行return	 回调

6.3、保证队列持久化消息

DeliveryMode设置消息持久化

//6.3、设置消息持久化AMQP.BasicProperties prop =new AMQP.BasicProperties().builder().deliveryMode(2)//消息持久化.build();//4. 发布消息channel.basicPublish("",QUEUE_NAME,true,prop,message.getBytes());

6.4、保证消息者可以正常消费消息

详情看WorkQueue模式

6.5 SpringBoot实现上述操作

6.5.1 Confirm

• 编写配置文件开启Confirm机制

spring:
rabbitmq:
publisher-confirm-type: correlated # 新版本 开启confirm机制
publisher-confirms: true # 老版本

• 在发送消息时，配置RabbitTemplate

@Testpublic void publishWithConfirms() throws IOException {rabbitTemplate.setConfirmCallback(new RabbitTemplate.ConfirmCallback() {@Overridepublic void confirm(CorrelationData correlationData, boolean b, String s) {if(b){System.out.println("消息已经送达到交换机");}else{System.out.println("消息没有送到到Exchange，需要做一些补偿操作！");}}});rabbitTemplate.convertAndSend(RabbitMQConfig.EXCHANGE,"big.black.dog","message");System.out.println("消息发送成功");System.in.read();}

6.5.2 Return

• 编写配置文件开启Return机制

spring:
rabbitmq:
publisher-returns: true # 开启return机制

• 在发送消息时，配置RabbitTemplate

@Testpublic void publishWithReturn() throws IOException {rabbitTemplate.setReturnCallback(new RabbitTemplate.ReturnCallback() {@Overridepublic void returnedMessage(Message message, int i, String s, String s1, String s2) {String msg = new String(message.getBody());System.out.println("消息失败："+msg+"路由队列失败！！做补救操作");}});rabbitTemplate.convertAndSend(RabbitMQConfig.EXCHANGE,"big.black.dog","message");System.out.println("消息发送成功");System.in.read();}

6.5.3 消息持久化

//3.4、设置消息持久化
AMQP.BasicProperties prop =new AMQP.BasicProperties().builder().deliveryMode(2)//消息持久化 #1.build();//4. 发布消息，  将参数mandatory设置为true，即可开启Return机制，当消息没有路由到队列中时，就会执行return回调channel.basicPublish("",QUEUE_NAME,true,prop,message.getBytes());

七、RabbitMQ死信队列 & 延迟交换机

###7.1、 消息被消费者拒绝，requeue设置为false
###7.2.1、发送消息时设置消息的生存时间，如果生存时间到了，还没有被消费。
###7.2.2、 也可以指定某个队列中所有消息的生存时间，如果生存时间到了，还没有被消费
###7.3、队列已经达到消息的最长长度后，再路由过来的消息直接变成死信

7.4、准备Exchange&Queue

@Configuration
public class DeadLetterConfig {public static final String NORMAL_EXCHANGE="normal-exchange";public static final String NORMAL_QUEUE="normal-queue";public static final String NORMAL_ROUTING_KEY="normal.#";public static final String DEAD_EXCHANGE="dead-exchange";public static final String DEAD_QUEUE="dead-queue";public static final String DEAD_ROUTING_KEY="dead.#";/**普通交换机*/@Beanpublic Exchange normalExchange(){return ExchangeBuilder.topicExchange(NORMAL_EXCHANGE).build();}/**普通队列*/@Beanpublic Queue normalQueue(){return QueueBuilder.durable(NORMAL_QUEUE).deadLetterExchange(DEAD_EXCHANGE)//绑定死信队列.build();}/**普通队列绑定路由*/@Beanpublic Binding normalBingding(Queue normalQueue,Exchange normalExchange){return BindingBuilder.bind(normalQueue).to(normalExchange).with(DEAD_ROUTING_KEY).noargs();}/**死信交换机*/@Beanpublic Exchange deadExchange(){return ExchangeBuilder.topicExchange(DEAD_EXCHANGE).build();}/**死信队列*/@Beanpublic Queue deadQueue(){return QueueBuilder.durable(DEAD_QUEUE ).build();}/**绑定死信队列和交换机*/@Beanpublic Binding deadBinding(Queue deadQueue,Exchange deadExchange){return BindingBuilder.bind(deadQueue).to(deadExchange).with(DEAD_ROUTING_KEY).noargs();}
}

7.5、实现效果

• 基于消费者进行reject 或者 nack 实现死信效果

@Component
public class DeadListener {/**** @param msg* @param channel 需要手动启动ACK 才能有效 spring.rabbitmq.listener.simple.acknowledge-mode: manual* @param message 需要手动启动ACK 才能有效 spring.rabbitmq.listener.simple.acknowledge-mode: manual*/@RabbitListener(queues = DeadLetterConfig.NORMAL_QUEUE)public void comsume(String msg, Channel channel, Message message) throws IOException {System.out.println("接收到normal队列的消息："+msg);
//        channel.basicReject(message.getMessageProperties().getDeliveryTag(),false);channel.basicNack(message.getMessageProperties().getDeliveryTag(),false,false);}
}

• 消息的生存时间

八、RabbitMQ的集群