精通SpringBoot---整合RabbitMQ消息队列

今天来和朋友们一起学习下，SpringBoot怎么整合RabbitMQ。目前消息组件大致有三种：.activemq, rabbitmq, kafka。这三者各有优缺点，RabbitMQ相比之下是处于其他二者之间的一个消息组件。RabbitMQ依赖于erlang，在linux下安装的话，要先安装erlang环境。下面来看看怎么SpringBoot 怎么整合RabbitMQ吧。

1. 想要使用RabbitMQ ，pom依赖是少不了的~

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

2.再来看看application.yml文件的内容

spring:
  rabbitmq:
    username: rabbit
    password: 123456
    host: localhost
    port: 5672
    virtual-host: /
    #手动ACK 不开启自动ACK模式,目的是防止报错后未正确处理消息丢失 默认 为 none
    listener:
      simple:
        acknowledge-mode: manual

RabbitMQConfig的内容（注册）

import org.springframework.amqp.core.Queue;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class RabbitMQConfig {

    public static final String DEFAULT_MAIL_QUEUE = "dev.mail.register.default.queue";

    public static final String MANUAL_MAIL_QUEUE = "dev.mail.register.manual.queue";

    @Bean
    public Queue defaultMailQueue (){
        // Queue queue = new  Queue(Queue名称，消息是否需要持久化处理)
        return new Queue(DEFAULT_MAIL_QUEUE, true);
    }

    @Bean
    public Queue manualMailQueue(){
        return new Queue(MANUAL_MAIL_QUEUE, true);
    }
}

搞两个监听器（使用@RabbitListener注解）来监听下这两种消息 (怎么感觉自己现在说话一股土味儿，最近吃土吃多了么~ 好吧，写的代码估计也是土味的吧）（监听队列）

import com.developlee.rabbitmq.config.RabbitMQConfig;
import com.developlee.rabbitmq.entity.MailEntity;
import com.rabbitmq.client.Channel;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.amqp.core.Message;
import org.springframework.amqp.rabbit.annotation.RabbitListener;
import org.springframework.stereotype.Component;

import java.io.IOException;
@Component
public class MailHandler {

    private static final Logger logger = LoggerFactory.getLogger(MailHandler.class);

    /**
     * <p>TODO 该方案是 spring-boot-data-amqp 默认的方式,不太推荐。具体推荐使用  listenerManualAck()</p>
     * 默认情况下,如果没有配置手动ACK, 那么Spring Data AMQP 会在消息消费完毕后自动帮我们去ACK
     * 存在问题：如果报错了,消息不会丢失,但是会无限循环消费,一直报错,如果开启了错误日志很容易将磁盘空间耗完
     * 解决方案：手动ACK,或者try-catch 然后在 catch 里面讲错误的消息转移到其它的系列中去
     * spring.rabbitmq.listener.simple.acknowledge-mode=manual
     * <p>
     *
     * @param mail 监听的内容
     */
    @RabbitListener(queues = {RabbitMQConfig.DEFAULT_MAIL_QUEUE})
    public void listenerAutoAck(MailEntity mail, Message message, Channel channel) {
        //TODO  如果手动ACK,消息会被监听消费,但是消息在队列中依旧存在,如果 未配置 acknowledge-mode 默认是会在消费完毕后自动ACK掉
        final long deliveryTag = message.getMessageProperties().getDeliveryTag();
        try {
            logger.info("listenerAutoAck 监听的消息-{}", mail.toString());
            //TODO  通知MQ 消息已被成功消费，可以ACK了
            channel.basicAck(deliveryTag, false);
        } catch (IOException e) {
            //处理失败， 重新压入MQ.
            try {
                channel.basicRecover();
            } catch (IOException e1) {
                e1.printStackTrace();
            }
        }
    }

    @RabbitListener(queues = {RabbitMQConfig.MANUAL_MAIL_QUEUE})
    public void listenerManualAck(MailEntity mail, Message message, Channel channel) {
        logger.info("listenerManualAck 监听的消息-{}", mail.toString());
        try {
            //TODO  通知MQ 消息已被成功消费，可以ACK了
            channel.basicAck(message.getMessageProperties().getDeliveryTag(), false);
        } catch (Exception e) {
            //如果报错，容错处理，
        }
    }
}

再来一波测试代码，测试下......（实例化队列）

import com.developlee.rabbitmq.config.RabbitMQConfig;
import com.developlee.rabbitmq.entity.MailEntity;
import org.springframework.amqp.rabbit.core.RabbitTemplate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * @author Lee
 * @// TODO 2018/6/22-11:20
 * @description
 */
@RestController
@RequestMapping(value = "/mail")
public class MailController {
    private final RabbitTemplate rabbitTemplate;

    @Autowired
    public MailController(RabbitTemplate rabbitTemplate) {
        this.rabbitTemplate = rabbitTemplate;
    }

    /**
     * this.rabbitTemplate.convertAndSend(RabbitConfig.DEFAULT_MAIL_QUEUE, mailEntity);
     * 对应 {@link MailHandler#listenerAutoAck};
     * this.rabbitTemplate.convertAndSend(RabbitConfig.MANUAL_MAIL_QUEUE, mailEntity);
     * 对应 {@link MailHandler#listenerManualAck};
     */
    @GetMapping("/default")
    public void defaultMailMsg() {
        MailEntity mailEntity = new MailEntity();
        mailEntity.setId("1");
        mailEntity.setName("First Mail Message");
        mailEntity.setTitle("RabbitMQ with Spring boot!");
        mailEntity.setContent("Come on! Let's study Micro-Service together!");
        this.rabbitTemplate.convertAndSend(RabbitMQConfig.DEFAULT_MAIL_QUEUE, mailEntity);
        this.rabbitTemplate.convertAndSend(RabbitMQConfig.MANUAL_MAIL_QUEUE, mailEntity);
    }
}

MailEntity.java

import java.io.Serializable;

public class MailEntity implements Serializable {

    private static final long serialVersionUID = -2164058270260403154L;

    private String id;
    private String name;
    private String title;
    private String content;

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getContent() {
        return content;
    }

    public void setContent(String content) {
        this.content = content;
    }
}

启动项目 ，浏览器地址栏输入http://localhost:8080/mail。 something you will find in your heart。