Spring Boot教程第15篇:Rabbitmq

2017/05/15

这篇文章带你了解怎么整合RabbitMQ服务器,并且通过它怎么去发送和接收消息。我将构建一个springboot工程,通过RabbitTemplate去通过MessageListenerAdapter去订阅一个POJO类型的消息。

准备工作

  • 15min
  • IDEA
  • maven 3.0

在开始构建项目之前,机器需要安装rabbitmq,你可以去官网下载,http://www.rabbitmq.com/download.html ,如果你是用的Mac(程序员都应该用mac吧),你可以这样下载:

brew install rabbitmq

安装完成后开启服务器:

rabbitmq-server

开启服务器成功,你可以看到以下信息:

            RabbitMQ 3.1.3. Copyright (C) 2007-2013 VMware, Inc.
##  ##      Licensed under the MPL.  See http://www.rabbitmq.com/
##  ##
##########  Logs: /usr/local/var/log/rabbitmq/rabbit@localhost.log
######  ##        /usr/local/var/log/rabbitmq/rabbit@localhost-sasl.log
##########
            Starting broker... completed with 6 plugins.


构建工程

构架一个SpringBoot工程,其pom文件依赖加上spring-boot-starter-amqp的起步依赖:

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

创建消息接收者

在任何的消息队列程序中,你需要创建一个消息接收者,用于响应发送的消息。


@Component
public class Receiver {

    private CountDownLatch latch = new CountDownLatch(1);

    public void receiveMessage(String message) {
        System.out.println("Received <" + message + ">");
        latch.countDown();
    }

    public CountDownLatch getLatch() {
        return latch;
    }

}

消息接收者是一个简单的POJO类,它定义了一个方法去接收消息,当你注册它去接收消息,你可以给它取任何的名字。其中,它有CountDownLatch这样的一个类,它是用于告诉发送者消息已经收到了,你不需要在应用程序中具体实现它,只需要latch.countDown()就行了。

创建消息监听,并发送一条消息

在spring程序中,RabbitTemplate提供了发送消息和接收消息的所有方法。你只需简单的配置下就行了:

  • 需要一个消息监听容器
  • 声明一个quene,一个exchange,并且绑定它们
  • 一个组件去发送消息

代码清单如下:

package com.forezp;

import com.forezp.message.Receiver;
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.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;


@SpringBootApplication
public class SpringbootRabbitmqApplication {

	 final static String queueName = "spring-boot";

	@Bean
	Queue queue() {
		return new Queue(queueName, false);
	}

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

	@Bean
	Binding binding(Queue queue, TopicExchange exchange) {
		return BindingBuilder.bind(queue).to(exchange).with(queueName);
	}

	@Bean
	SimpleMessageListenerContainer container(ConnectionFactory connectionFactory,
											 MessageListenerAdapter listenerAdapter) {
		SimpleMessageListenerContainer container = new SimpleMessageListenerContainer();
		container.setConnectionFactory(connectionFactory);
		container.setQueueNames(queueName);
		container.setMessageListener(listenerAdapter);
		return container;
	}

	@Bean
	MessageListenerAdapter listenerAdapter(Receiver receiver) {
		return new MessageListenerAdapter(receiver, "receiveMessage");
	}


	public static void main(String[] args) {
		SpringApplication.run(SpringbootRabbitmqApplication.class, args);
	}
}


创建一个测试方法:


@Component
public class Runner implements CommandLineRunner {

    private final RabbitTemplate rabbitTemplate;
    private final Receiver receiver;
    private final ConfigurableApplicationContext context;

    public Runner(Receiver receiver, RabbitTemplate rabbitTemplate,
            ConfigurableApplicationContext context) {
        this.receiver = receiver;
        this.rabbitTemplate = rabbitTemplate;
        this.context = context;
    }

    @Override
    public void run(String... args) throws Exception {
        System.out.println("Sending message...");
        rabbitTemplate.convertAndSend(Application.queueName, "Hello from RabbitMQ!");
        receiver.getLatch().await(10000, TimeUnit.MILLISECONDS);
        context.close();
    }

}

启动程序,你会发现控制台打印:

Sending message...
Received <Hello from RabbitMQ!>

总结

恭喜!你刚才已经学会了如何通过spring raabitmq去构建一个消息发送和订阅的程序。 这仅仅是一个好的开始,你可以通过spring-rabbitmq做更多的事,点击这里

源码下载:https://github.com/forezp/SpringBootLearning

参考资料

https://spring.io/guides/gs/messaging-rabbitmq/

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本文为原创文章,转载请标明出处。
本文链接:http://blog.fangzhipeng.com/springboot/2017/05/15/sb15-rabbitmq.html
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