SpringBoot的RabbitMQ消息队列: 六、第五模式"Topics"

Topics模式，官方的解释是Receiving messages based on a pattern (topics)，它的结构是

消费者各自监控自己的队列；交换机通过一种模式策略确定生产者的消息放入那个队列。

1、建立工程， 通过http://start.spring.io，建立Topic工程

2、下载、解压，导入eclipse

3、修改pom.xml,以便于热部署

4、增加日志文件logback.xml

5、修改application.properties

   #服务器配置  
    spring.application.name=rabbitmq-topic  
    server.port=9080   
    #rabbitmq连接参数  
    spring.rabbitmq.host=localhost  
    spring.rabbitmq.port=5672  
    spring.rabbitmq.username=test  
    spring.rabbitmq.password=123456  

6、配置文件。增加类TopicRabbitConfig，编制代码为

package com.example;

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.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class TopicRabbitConfig {

	final static String message = "topic.message";
    final static String messages = "topic.messages";

    @Bean
    public Queue queueMessage() {
        return new Queue(TopicRabbitConfig.message);
    }

    @Bean
    public Queue queueMessages() {
        return new Queue(TopicRabbitConfig.messages);
    }

    @Bean
    TopicExchange exchange() {
        return new TopicExchange("exchange");
    }

    @Bean
    Binding bindingExchangeMessage(Queue queueMessage, TopicExchange exchange) {
        return BindingBuilder.bind(queueMessage).to(exchange).with("topic.message");
    }

    @Bean
    Binding bindingExchangeMessages(Queue queueMessages, TopicExchange exchange) {
        return BindingBuilder.bind(queueMessages).to(exchange).with("topic.#");
    }
}

7、消息发送。增加类TopicSender，编制代码为

package com.example;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.amqp.core.AmqpTemplate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

@Component
public class TopicSender {


	protected static Logger logger=LoggerFactory.getLogger(TopicSender.class); 
	
	@Autowired
    private AmqpTemplate rabbitTemplate;
	public void send1() {
	    String context = "hi, i am message 1";
	    logger.debug("Sender : " + context);
	    this.rabbitTemplate.convertAndSend("exchange", "topic.message", context);
	}

	public void send2() {
	    String context = "hi, i am messages 2";
	    logger.debug("Sender : " + context);
	    this.rabbitTemplate.convertAndSend("exchange", "topic.messages", context);
	}
}

8、消息接收1.增加类TopicReceiver，编制代码为

package com.example;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.amqp.rabbit.annotation.RabbitHandler;
import org.springframework.amqp.rabbit.annotation.RabbitListener;
import org.springframework.stereotype.Component;

@Component
@RabbitListener(queues = "topic.message")
public class TopicReceiver {

	protected static Logger logger=LoggerFactory.getLogger(TopicReceiver.class); 
	
    @RabbitHandler
    public void process(String message) {
        logger.debug("Topic Receiver1  : " + message);
    }

}

9、消息接收2.增加类TopicReceiver2，编制代码为

package com.example;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.amqp.rabbit.annotation.RabbitHandler;
import org.springframework.amqp.rabbit.annotation.RabbitListener;
import org.springframework.stereotype.Component;

@Component
@RabbitListener(queues = "topic.messages")
public class TopicReceiver2 {
	
	protected static Logger logger=LoggerFactory.getLogger(TopicReceiver2.class); 
	

    @RabbitHandler
    public void process(String message) {
        logger.debug("Topic Receiver2  : " + message);
    }

}

10、RestController。增加类TopicController，编制代码为

package com.example;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class TopicController {
	
	@Autowired
    private TopicSender topicSender;
	
	@RequestMapping("/send1")
	public String send1() {
		topicSender.send1();
		return "send1 ok";
	}
	
	@RequestMapping("/send2")
	public String send2() {
		topicSender.send2();
		return "send2 ok";
	}
}

11、运行工程。在工程所在文件夹打开cmd,输入mvn spring-boot:run

12、在浏览器中分别输入http://localhost:9080/send1 ,http://localhost:9080/send2,查看控制台输出
http://localhost:9080/send1,控制台的输出，两个接收器都收到消息

http://localhost:9080/send2,控制台的输出，第二个接收器收到消息

13、小结

A、在配置文件中，定义了一个TopicExchange,然后对两个队列，分别配置了绑定规则。（变更绑定规则测试时，先停止命令行的spring-boot，再删除rabbitmq management中的队列）。

B、发送器，发送send1会匹配到topic.#和topic.message 两个Receiver都可以收到消息，发送send2只有topic.#可以匹配所有只有Receiver2监听到消息。

     发送器在发送消息时，使用的方法是需要传入一个特定的交换机的。

C、接收器，依然各自监控自己的队列；