這篇文章帶你瞭解怎麼整合RabbitMQ伺服器，並且通過它怎麼去傳送和接收訊息。我將構建一個springboot工程，通過RabbitTemplate去通過MessageListenerAdapter去訂閱一個POJO型別的訊息。

準備工作

• 15min
• IDEA
• maven 3.0

在開始構建專案之前，機器需要安裝rabbitmq，你可以去官網下載，http://www.rabbitmq.com/download.html ，如果你是用的Mac，你可以這樣下載：

brew install rabbitmq

安裝完成後開啟伺服器：

rabbitmq-server

開啟伺服器成功，你可以看到以下資訊：

           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.

構建工程

構架一個SpringBoot工程，其pom檔案依賴加上spring-boot-starter-amqp的起步依賴：

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

建立訊息接收者

在任何的訊息佇列程式中，你需要建立一個訊息接收者，用於響應傳送的訊息。

@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;
    }

}

訊息接收者是一個簡單的POJO類，它定義了一個方法去接收訊息，當你註冊它去接收訊息，你可以給它取任何的名字。其中，它有CountDownLatch這樣的一個類，它是用於告訴傳送者訊息已經收到了，你不需要在應用程式中具體實現它，只需要latch.countDown()就行了。

建立訊息監聽，併發送一條訊息

在spring程式中，RabbitTemplate提供了傳送訊息和接收訊息的所有方法。你只需簡單的配置下就行了：

• 需要一個訊息監聽容器
• 宣告一個quene,一個exchange,並且繫結它們
• 一個元件去傳送訊息

程式碼清單如下：

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);
    }
}

建立一個測試方法：

@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();
    }

}

啟動程式，你會發現控制檯列印 

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