实战代码（七）：Springboot集成RocketMQ

作者: LY丶Smile | 来源:发表于2020-12-10 21:51 被阅读0次

一、理论基础

1.1 RocketMQ能用来做什么

消息通讯

消息通讯是最基本也是最为简单的应用。比较典型的一个应用场景就是没有公网IP的情况下，外界服务无法访问接口，可以使用消息队列来订阅事件来实现双向通信。

异步处理

对于处理频繁且不需要即时反馈的场景来讲，RocketMQ具备良好的性能，而且比较优秀的消息堆积处理能力对于异步操作来说也是加分项。

其余功能

比如流量削峰、应用解耦等，具体可看下网上对于该功能的详细讲解，本文不做深入。

1.2 基础概念

Topic：主题，一级消息类型，可以配合Tag使用做细致区分，不同类型的消息设置不同Topic
Tag：消息标签，二级消息类型，用于进一步区分某个Topic下的消息分类
Producer：生产者，发送消息
Consumer：消费者，一个消息可以被多个消费者订阅
Consumer Group：消费者分组，为了实现集群消费，不同Consumer Group之间消费进度彼此不受影响，一个Consumer Group下包含多个Consumer实例
Producer Group：生产者分组，标识发送同一类消息的Producer，通常发送逻辑一致，一个Producer Group可以发送多个Topic消息

1.3 简单说明

GitHub上有一个开源的RocketMQ工具：RocketMQ-Spring
感兴趣的可以研究一下，功能实现很完整。

二、实战代码

2.1 依赖引入

<dependency>
   <groupId>org.apache.rocketmq</groupId>
   <artifactId>rocketmq-client</artifactId>
   <version>4.7.0</version>
</dependency>

<!-- 自定义的元数据依赖 -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-configuration-processor</artifactId>
    <optional>true</optional>
</dependency>

2.2 配置项

rocketmq:
  # rocketmqClient日志路径，默认是系统登录用户的根目录
  producer:
    clientLogDir: logs/rocketmq_client
    # 日志级别
    clientLogLevel: WARN
    namesrvAddr: 127.0.0.1:9876
    groupName: test
    retryTimesWhenSendAsyncFailed: 1
    sendMsgTimeout: 6000
    brokerName: broker-a
  consumer:
    # 日志级别
    clientLogLevel: WARN
    namesrvAddr: 127.0.0.1:9876
    groupName: test
    threadMax: 20
    threadMin: 10

备注：对于服务器硬盘不大的机器来讲，一定要记得设置RocketMQ的日志级别和路径等，否则增长极快的日志文件很快就会将你的硬盘塞满。而且如果没有后续的日志搜集与分析需求，很多日志没必要打印。

2.3 配置文件读取

2.3.1 producer

/**
 * RocketMQ Producer 配置项
 * @author smile
 */
@Component
@ConfigurationProperties(prefix = "rocketmq.producer")
@Data
public class ProducerProperties {

    private String clientLogDir;
    private String clientLogLevel;
    private String namesrvAddr;
    private String groupName;
    private int retryTimesWhenSendAsyncFailed;
    private int sendMsgTimeout;

}

2.3.2 consumer

/**
 * RocketMQ consumer配置项
 * @author smile
 */
@Component
@ConfigurationProperties(prefix = "rocketmq.consumer")
@Data
public class ConsumerProperties {

    private String namesrvAddr;
    private int threadMax;
    private int threadMin;
    private String groupName;
    private String clientLogDir;
    private String clientLogLevel;
}

2.4 producer初始化

/**
 * 程序启动时初始化Producer
 * @author smile
 */
@Configuration
@Slf4j
public class ProducerConfig {

    private final ProducerProperties properties;

    public ProducerConfig(ProducerProperties properties) {
        this.properties = properties;
    }

    @Bean
    public DefaultMQProducer getRocketMQProducer() throws MQClientException {
        setClientProperty();
        DefaultMQProducer producer = new DefaultMQProducer(properties.getGroupName());
        producer.setNamesrvAddr(properties.getNamesrvAddr());
        producer.setRetryTimesWhenSendAsyncFailed(properties.getRetryTimesWhenSendAsyncFailed());
        producer.setSendMsgTimeout(properties.getSendMsgTimeout());
        producer.start();
        log.info("*** producer has started! groupName:[{}], namesrvAddr:[{}] ***", properties.getGroupName(), properties.getNamesrvAddr());
        return producer;
    }

    private void setClientProperty() {
        System.setProperty(ClientLogger.CLIENT_LOG_ROOT, properties.getClientLogDir());
        System.setProperty(ClientLogger.CLIENT_LOG_LEVEL, properties.getClientLogLevel());
    }
}

2.5 consumer示例代码

2.5.1 Consumer管理程序

本实例基于一个Group的Consumer。简单测试过，未做生产环境的深度测试

可实现简单的Consumer初始化、新增订阅、取消订阅功能

/**
 * @author smile
 */
@Slf4j
public class ConsumerManager {

    private static final ConsumerManager MANAGER = new ConsumerManager();
    private static final String TAGS_SEP = "||";
    private static Map<String, String> subscription = new HashMap<String, String>(8) {
        {
            // 系统消息：订阅与取消订阅的事件
            put("sys", "subscribe||unsubscribe");
        }
    };

    private static DefaultMQPushConsumer consumer;


    /**
     * 单例，不允许外界主动实例化
     */
    private ConsumerManager() {
    }

    public static ConsumerManager getInstance() {
        return MANAGER;
    }

    /**
     * 初始化Consumer，本示例初始化一个ConsumerGroup
     * 后续所有的订阅与取消订阅都是在一个consumer实例下进行
     */
    public void initConsumer(ConsumerProperties properties) throws MQClientException {
        // 设置client日志信息, producer初始化时已配置，此处不再配置
//        System.setProperty(ClientLogger.CLIENT_LOG_ROOT, properties.getClientLogDir());
//        System.setProperty(ClientLogger.CLIENT_LOG_LEVEL, properties.getClientLogLevel());

        consumer = new DefaultMQPushConsumer(properties.getGroupName());
        consumer.setNamesrvAddr(properties.getNamesrvAddr());
        consumer.setConsumeThreadMax(properties.getThreadMax());
        consumer.setConsumeThreadMin(properties.getThreadMin());
        consumer.setConsumeFromWhere(ConsumeFromWhere.CONSUME_FROM_LAST_OFFSET);
        log.info("consumer topic and tags : {}", subscription);
        for (Map.Entry<String, String> entry : subscription.entrySet()) {
            consumer.subscribe(entry.getKey(), entry.getValue());
        }
        consumer.registerMessageListener((MessageListenerConcurrently) (msgs, context) -> {
            try {
                MessageExt msg = msgs.get(0);
                String msgBody = new String(msg.getBody(), "utf-8");
                log.info("receive message, messageId:[{}], messageBody:{}， topic:[{}], tag:[{}]",
                        msg.getMsgId(), msgBody, msg.getTopic(), msg.getTags());
                log.info("delay: [{}] ms", (System.currentTimeMillis() - msg.getBornTimestamp()));
            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
                // 如果执行异常，则稍后会重新消费
                return ConsumeConcurrentlyStatus.RECONSUME_LATER;
            }
            return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
        });
        consumer.start();
        log.info("consumer has started! NamesrvAddr:[{}], groupName:[{}]", properties.getNamesrvAddr(), properties.getGroupName());
    }


    /**
     * 订阅新的事件
     * @param topic topic
     * @param tags tags，支持多个tag订阅，格式：TagA||TagB
     * @throws MQClientException
     */
    public void subscribe(String topic, String tags) throws MQClientException {
        if (subscription.containsKey(topic)) {
            tags = StringUtils.join(subscription.get(topic), TAGS_SEP, tags);
        }
        consumer.subscribe(topic, tags);
        subscription.put(topic, tags);
        log.info("!!刷新订阅, {}", subscription);
    }

    /**
     * 取消订阅
     */
    public void unsubscribe(String topic, String tags) throws MQClientException {
        if (!subscription.containsKey(topic)) {
            log.error("topic is not found");
            return;
        }
        String[] unsubscribeTags = tags.trim().split("\\|\\|");
        String[] existingTags = subscription.get(topic).trim().split("\\|\\|");
        log.info("unsubscribeTags: {}, existingTags: {}", unsubscribeTags, existingTags);
        StringBuilder newTagsBuilder = new StringBuilder();
        for (String existingTag : existingTags) {
            if (!ArrayUtils.contains(unsubscribeTags, existingTag)) {
                newTagsBuilder.append(existingTag).append(TAGS_SEP);
            }
        }

        if (tags.length() == 0) {
            consumer.unsubscribe(topic);
            return;
        }

        String newTags = newTagsBuilder.substring(0, newTagsBuilder.length() - 2);
        log.info("newTags: {}", newTagsBuilder);
        consumer.subscribe(topic, newTags);
        subscription.put(topic, newTags);
        log.info("!!取消订阅，新的订阅列表, {}", subscription);
    }

}

2.5.2 初始化Consumer

/**
 * @author smile
 */
@Component
public class ConsumerInit implements CommandLineRunner {

    private final ConsumerProperties properties;

    public ConsumerInit(ConsumerProperties properties) {
        this.properties = properties;
    }

    @Override
    public void run(String... args) throws Exception {
        ConsumerManager.getInstance().initConsumer(properties);
    }
}

三、源码地址

完整示例代码,请移步GitHub

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