RabbitMQ入门（六）RabbitMQ交换器之fanout

前言

      本章讲解RabbitMQ常用交换器的最后一个类型——fanout

方法

1.概念

fanout（广播），顾名思义，其可以不依赖路由键，向所有绑定了的队列发送消息。

广播的含义就是将消息发送给所有订阅该频道的听众。

需求：我们的用户下订单之后，我们会做如下的两步操作：发短信、推送订单，在以前的模式上，我们下订单的业务逻辑和发短信，推送订单的逻辑是强耦合的，当我们使用RabbitMQ之后，情况将变得十分乐观。我们可以为发短信和推送订单业务各设立一个队列，当用户下订单的时候，会将消息同时传递给这两个队列，进而进行后续的发短信和推送订单业务，实现解耦。

2.环境搭建

1）创建Provider和Consumer工程

2）修改pom文件

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.1.7.RELEASE</version>
	</parent>
	<groupId>cn.edu.ccut</groupId>
	<artifactId>rabbitmq-fanout-consumer</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	
	<properties>
		<!-- 设定Java的版本 -->
		<java.version>1.8</java.version>
		<!-- 解决pom.xml首行报错 -->
		<maven-jar-plugin.version>3.1.0</maven-jar-plugin.version>
	</properties>
	
	<dependencies>
		<!-- 配置springBoot的web启动器 -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
		<!-- 配置rabbitmq的启动器 -->
		<dependency>
		    <groupId>org.springframework.boot</groupId>
		    <artifactId>spring-boot-starter-amqp</artifactId>
		</dependency>
		<!-- 配置devtools  -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-devtools</artifactId>
		</dependency>
		<!-- 配置springBoot的test启动器 -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
		</dependency>
	</dependencies>
	
	 <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <mainClass>cn.edu.ccut.App</mainClass>
                </configuration>
            </plugin>
        </plugins>
    </build>
    
</project>

3）修改application.properties

Provider：

spring.application.name=springboot-rabbitmq
#rabbitmq config
spring.rabbitmq.host=192.168.1.108
spring.rabbitmq.port=5672
spring.rabbitmq.username=jwang
spring.rabbitmq.password=123456

#exchange config
mq.config.exchange=order.fanout

Consumer：

spring.application.name=springboot-rabbitmq
#rabbitmq config
spring.rabbitmq.host=192.168.1.108
spring.rabbitmq.port=5672
spring.rabbitmq.username=jwang
spring.rabbitmq.password=123456

#exchange config
mq.config.exchange=order.fanout

mq.config.queue.sms=order.sms

mq.config.queue.push=order.push

3.编写Consumer代码

创建两个Consumer类，PushConsumer和SmsConsumer来分别处理订单的推送和短信功能

注意：广播模式不需要路由键啦！

PushConsumer:

package cn.edu.ccut;

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.RabbitHandler;
import org.springframework.amqp.rabbit.annotation.RabbitListener;
import org.springframework.stereotype.Component;

@Component
@RabbitListener(bindings=
		@QueueBinding(
				value=@Queue(name="${mq.config.queue.push}",autoDelete="true"),
				exchange=@Exchange(name="${mq.config.exchange}",type=ExchangeTypes.FANOUT)
		)
)
public class PushConsumer {

	@RabbitHandler
	public void receiveMsg(String msg){
		System.out.println("Push Message is "+msg);
	}
}

SmsConsumer：

package cn.edu.ccut;

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.RabbitHandler;
import org.springframework.amqp.rabbit.annotation.RabbitListener;
import org.springframework.stereotype.Component;

@Component
@RabbitListener(bindings=
		@QueueBinding(
				value=@Queue(name="${mq.config.queue.sms}",autoDelete="true"),
				exchange=@Exchange(name="${mq.config.exchange}",type=ExchangeTypes.FANOUT)
		)
)
public class SmsConsumer {

	@RabbitHandler
	public void receiveMsg(String msg){
		System.out.println("Sms Message is "+msg);
	}
}

4.编写Provider

Provider:

package cn.edu.ccut;

import org.springframework.amqp.core.AmqpTemplate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

@Component
public class Provider {

	@Autowired
	private AmqpTemplate rabbitTemplate;
	@Value("${mq.config.exchange}")
	private String exchange;
	
	public void sendMsg(String msg){
		rabbitTemplate.convertAndSend(exchange, "", msg);
	}
}

注意：此处不需要传递路由键啦！

5.编写测试代码进行测试

package cn.edu.ccut;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

@RunWith(SpringRunner.class)
@SpringBootTest(classes=App.class)
public class RabbitMQTest {
	
	@Autowired
	private Provider provider;
	
	@Test
	public void testSendMsg() throws Exception{
		provider.sendMsg("hello rabbitmq !");
	}
}

接下来我们首先启动消费者端：

再次运行我们测试代码，观察控制台效果：

我们发现，SMS和Push端都接收到了消息，可见我们的测试是成功的。