RocketMQ 学习笔记

为什么选择 RocketMQ ？

比较一下其他的消息中间件：

最关键的是，RocketMQ 是 Java 写的。。。易于学习

• 先要用起来，然后看文档，读源码

• 官方文档 链接: 官方文档当然也是要看的

• Github 链接: 看源码肯定是必须的就不多说什么了

安装 RocketMQ

1. 下载地址：http://rocketmq.apache.org/release_notes/release-notes-4.7.0

2. 配置环境变量

3. 启动 NAMESERVER

> mqnamesrv

4. 启动 BROCKER

> mqbroker -n 127.0.0.1:9876 autoCreateTopicEnable=true

5. 安装可视化插件（可有可无的）
   下载
   Git地址：https://github.com/apache/rocketmq-externals
   gitee地址：https://gitee.com/mirrors/RocketMQ-Externals
   配置 application.properties 端口

> server.port=9876

Maven 编译运行 jar
进文件夹下

> mvn clean package -Dmaven.test.skip=true
> java -jar *.jar

引入 pom 依赖

<!-- rocketmq -->
<dependency>
    <groupId>org.apache.rocketmq</groupId>
    <artifactId>rocketmq-spring-boot-starter</artifactId>
    <version>2.1.1</version>
</dependency>

MQService

import org.apache.rocketmq.common.message.Message;
import org.apache.rocketmq.spring.core.RocketMQTemplate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class RocketMQService {
    @Autowired
    private RocketMQTemplate rocketMQTemplate;

    /**
     *  发送消息
     * @param topic
     * @param body
     * @throws Exception
     */
    public void sendMessage(String topic,String body) throws Exception{
        Message message = new Message(topic,body.getBytes());
        rocketMQTemplate.getProducer().send(message);
    }

    /**
     * 发送延时消息
     * @param topic
     * @param body
     * @param delayTimeLevel
     * @throws Exception
     */
    public void sendDelayMessage(String topic, String body, int delayTimeLevel) throws Exception {
        Message message = new Message(topic, body.getBytes());
        message.setDelayTimeLevel(delayTimeLevel);
        rocketMQTemplate.getProducer().send(message);
    }
}

测试监听

import org.apache.rocketmq.common.message.MessageExt;
import org.apache.rocketmq.spring.annotation.RocketMQMessageListener;
import org.apache.rocketmq.spring.core.RocketMQListener;
import org.springframework.stereotype.Component;
import java.io.UnsupportedEncodingException;

@Component
@RocketMQMessageListener(topic = "test-mq", consumerGroup = "conmuserGrop-mq")
public class ConsumerListener implements RocketMQListener<MessageExt> {
    @Override
    public void onMessage(MessageExt messageExt) {
        try {
            String body = new String(messageExt.getBody(), "UTF-8");
            System.out.println("receive message:" + body);
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }
    }
}

测试类

import com.jiuzhang.seckill.mq.RocketMQService;
import com.jiuzhang.seckill.service.SeckillActivityService;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import java.util.Date;

@SpringBootTest
public class MQTest {
    @Autowired
    RocketMQService rocketMQService;
    @Autowired
    SeckillActivityService seckillActivityService;
    @Test
    public void sendMQTest() throws Exception {
        rocketMQService.sendMessage("test-mq", "Hello RocketMQ!" + new Date().toString());
    }
}