RocketMQ自定义selector实现消息通道定向发送和拉取

RocketMQ的安装部署请参考官网Quick Start

RocketMQ的简单应用请参考官网github样例

本篇介绍如何通过自定义selector实现按messageQueue定向发送和接收消息

我们先看看MessageQueueSelector接口

public interface MessageQueueSelector {
    MessageQueue select(final List<MessageQueue> mqs, final Message msg, final Object arg);
}

 RocketMQ通过MessageQueueSelector中实现的算法来确定消息发送到哪一个队列上，RocketMQ默认提供了三种实现，分别是SelectMessageQueueByHash、SelectMessageQueueByMachineRoom、SelectMessageQueueByRandoom。MessageQueueSelector的select方法提供了三个入参，分别为消息队列集合、消息和扩展参数。本示例通过使用扩展参数来实现消息通道的定向发送和接收。

1、pom.xml引入rocketmq jar包

		<!-- 引入rocketmq -->
		<dependency>
			<groupId>com.alibaba.rocketmq</groupId>
			<artifactId>rocketmq-client</artifactId>
			<version>3.2.6</version>
		</dependency>
		
		<!-- 提供常用的lang包工具类 -->
		<dependency>
			<groupId>org.apache.commons</groupId>
			<artifactId>commons-lang3</artifactId>
			<version>3.3.2</version>
		</dependency>

 

2、MessageQueueSelector接口实现

package com.lh.rocketmq.selector;

import java.util.List;

import org.apache.commons.lang3.math.NumberUtils;

import com.alibaba.rocketmq.client.producer.MessageQueueSelector;
import com.alibaba.rocketmq.common.message.Message;
import com.alibaba.rocketmq.common.message.MessageQueue;

/**
 * 通过调用 producer.send(msg, new SelectMessageQueueByExtOrg() , queueId)指定发送通道
 *
 * @author lh
 * @since 2017-4-22
 * @version 1.0.0
 *
 */
public class SelectMessageQueueByExtOrg implements MessageQueueSelector {

	public MessageQueue select(List<MessageQueue> mqs, Message msg, Object arg) {
		return mqs.get(NumberUtils.toInt(arg.toString()));
	}

}

 

3、producer通过自定义的MessageQueueSelector 发送消息

package com.lh.rocketmq.producer;

import com.alibaba.rocketmq.client.exception.MQBrokerException;
import com.alibaba.rocketmq.client.exception.MQClientException;
import com.alibaba.rocketmq.client.producer.DefaultMQProducer;
import com.alibaba.rocketmq.client.producer.SendResult;
import com.alibaba.rocketmq.common.message.Message;
import com.alibaba.rocketmq.remoting.exception.RemotingException;
import com.lh.rocketmq.common.MqConst;
import com.lh.rocketmq.selector.SelectMessageQueueByExtOrg;
/**
 * producer通过自定义的MessageQueueSelector 发送消息
 * @author lh
 * @since 2017-4-23
 *
 */
public class ProducerByExtOrgSelector {

	public static void main(String[] args) {

		DefaultMQProducer producer = new DefaultMQProducer("Producer");
		producer.setNamesrvAddr(MqConst.NAME_SRV_ADDR);
		try {
			producer.start();
			int queueId = 0;
			for (int i = 0; i < 16000; i++) {
				queueId = i % 4;
				Message msg = new Message(MqConst.TOPIC_NAME, MqConst.TAG_PUSH + queueId, "key" + i, ("hello rocketmq " + i).getBytes());
				SendResult result = producer.send(msg, new SelectMessageQueueByExtOrg(), queueId);
				System.out.println("offset=" + result.getQueueOffset() + ", msgId=" + result.getMsgId() + ", sendStatus=" + result.getSendStatus());
			}

		} catch (MQClientException e) {
			e.printStackTrace();
		} catch (RemotingException e) {
			e.printStackTrace();
		} catch (MQBrokerException e) {
			e.printStackTrace();
		} catch (InterruptedException e) {
			e.printStackTrace();
		} finally {
			producer.shutdown();
		}
	}

}

     mq常量类

package com.lh.rocketmq.common;
/**
 * mq常量类
 * @author lh
 *
 */
public class MqConst {
	
	/**
	 * 服务地址
	 */
	public static final String NAME_SRV_ADDR = "192.168.191.130:9876";
	
	/**
	 * 主题名称
	 */
	public static final String TOPIC_NAME = "rocketmq-simple-demo";
	/**
	 * broker名称
	 */
	public static final String BROKER_NAME = "localhost.localdomain";
	
	/**
	 * tag
	 */
	public static final String TAG_PUSH = "push";
	
	/**
	 * 消息定向queueId 
	 * 对应Message.getUserProperty(MqConst.MESSAGE_KEY_QUEUE_ID)
	 */
	public static final String MESSAGE_KEY_QUEUE_ID="queueId";
	
	
	/**
	 * 测试队列和tag相同的标识
	 */
	public static final int TARGET_QUEUEID_TAG= 0;
	
	
	

}

4、通过指定的messageQueue拉取消息

package com.lh.rocketmq.consumer;

import java.nio.charset.Charset;
import java.util.List;

import com.alibaba.rocketmq.client.consumer.DefaultMQPullConsumer;
import com.alibaba.rocketmq.client.consumer.PullResult;
import com.alibaba.rocketmq.common.message.MessageExt;
import com.alibaba.rocketmq.common.message.MessageQueue;
import com.lh.rocketmq.common.MqConst;
/**
 * 通过指定的messageQueue拉取消息
 * @author lh
 * @since 2017-04-23
 *
 */
public class PullConsumerByQueueId {

	public static void main(String[] args) {
		long startTime = System.currentTimeMillis();
		DefaultMQPullConsumer consumer = new DefaultMQPullConsumer("PullConsumer");
		consumer.setNamesrvAddr(MqConst.NAME_SRV_ADDR);
		long offset = 0;
		long maxOffset = offset;

		try {
			consumer.start();
			MessageQueue mq = new MessageQueue(MqConst.TOPIC_NAME, MqConst.BROKER_NAME, MqConst.TARGET_QUEUEID_TAG);			
			do{
				PullResult result = consumer.pullBlockIfNotFound(mq, null, offset, 32);
				List<MessageExt> msgs = result.getMsgFoundList();
				if (msgs != null && msgs.size() != 0) {
					for (MessageExt msg : msgs) {
						System.out.println(new String(msg.getBody(), Charset.forName("utf-8")));
					}
				}
				offset = result.getNextBeginOffset();
				maxOffset = result.getMaxOffset();
				System.out.println("offset="+offset+", status="+result.getPullStatus());
			}while(offset < maxOffset);

		} catch (Exception e) {
			e.printStackTrace();
		}finally{
			consumer.shutdown();
			long endTime = System.currentTimeMillis();			
			System.out.println("PullConsumerByQueueId\t take times="+ (endTime - startTime));
		}

	}

}

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