Topic类型的Exchange与Direct相比，都是可以根据RoutingKey把消息路由到不同的队列。只不过Topic类型Exchange可以让队列在绑定Routing key 的时候使用通配符！

Routingkey 一般都是有一个或多个单词组成，多个单词之间以”.”分割，例如： snow.com

通配符规则：

#：匹配一个或多个词

*：匹配不多不少恰好1个词

举例：

snow.#：能够匹配snow.com.cn 或者 snow.com

snow.*：只能匹配snow.com

如下图:

解释：

• Queue1：绑定的是china.# ，因此凡是以 china.开头的routing key 都会被匹配到。包括china.news和china.weather
• Queue2：绑定的是#.news ，因此凡是以 .news结尾的 routing key 都会被匹配。包括china.news和japan.news

案例需求：
实现思路如下：

1. 并利用 @RabbitListener 声明 Exchange、Queue、RoutingKey
2. 在 consumer 服务中，编写两个消费者方法，分别监听 business.test.topic.queue1 和business.test.topic.queue2
3. 在 publisher 中编写测试方法，向business.test.topic发送消息

pom

    <dependencies><!--RabbitMQ 依赖--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-amqp</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>com.alibaba</groupId><artifactId>fastjson</artifactId><version>1.2.47</version></dependency><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId></dependency></dependencies>

yml

server:port: 8080
spring:rabbitmq:host: **.***.**.***port: 5672username: ****password: ****

生产者

import org.springframework.amqp.rabbit.core.RabbitTemplate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;/*** @author: Snow* @date: 2023/1/6* *************************************************** 修改记录(时间--修改人--修改说明):*/
@RestController
@RequestMapping("/topic")
public class SendController {@Autowiredprivate RabbitTemplate rabbitTemplate;@GetMapping("/send/{message}")public void send(@PathVariable("message") String message){// 交换机名称String exchangeName = "business.test.topic";// 发送消息if(message.contains("china") && message.contains("news")){rabbitTemplate.convertAndSend(exchangeName, "china.news", message);return;}if(message.contains("china")){rabbitTemplate.convertAndSend(exchangeName, "china.lala", message);return;}if(message.contains("news")){rabbitTemplate.convertAndSend(exchangeName, "lalla.news", message);return;}}}

消费者

import org.springframework.amqp.core.ExchangeTypes;
import org.springframework.amqp.rabbit.annotation.Exchange;
import org.springframework.amqp.rabbit.annotation.Queue;
import org.springframework.amqp.rabbit.annotation.QueueBinding;
import org.springframework.amqp.rabbit.annotation.RabbitListener;
import org.springframework.stereotype.Component;/*** @author: Snow* @date: 2023/1/6* *************************************************** 修改记录(时间--修改人--修改说明):*/
@Component
public class Consumer {@RabbitListener(bindings = @QueueBinding(value = @Queue(name = "business.test.topic.queue1"),exchange = @Exchange(name = "business.test.topic", type = ExchangeTypes.TOPIC),key = "china.#"))public void listenTopicQueue1(String msg){System.out.println("消费者接收到topic.queue1的消息：【" + msg + "】");}@RabbitListener(bindings = @QueueBinding(value = @Queue(name = "business.test.topic.queue2"),exchange = @Exchange(name = "business.test.topic", type = ExchangeTypes.TOPIC),key = "#.news"))public void listenTopicQueue2(String msg){System.out.println("消费者接收到topic.queue2的消息：【" + msg + "】");}
}