JAVA springboot微服务b2b2c电子商务系统 （十五）Springboot整合RabbitMQ

Posted 2021-02-03 sc-sc

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，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/[email protected]
        /usr/local/var/log/rabbitmq/[email protected]
            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 

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