RocketMQ消费消息

 一、测试用例

package com.mq.rocket.consumer;

import org.apache.rocketmq.client.consumer.DefaultMQPushConsumer;
import org.apache.rocketmq.client.consumer.listener.ConsumeConcurrentlyContext;
import org.apache.rocketmq.client.consumer.listener.ConsumeConcurrentlyStatus;
import org.apache.rocketmq.client.consumer.listener.MessageListenerConcurrently;
import org.apache.rocketmq.client.exception.MQClientException;
import org.apache.rocketmq.common.message.MessageExt;

import java.util.List;

/**
 * 消息接收者
 */
public class Consumer {
    public static void main(String[] args) throws MQClientException {
        // 1.创建消费者consumer，指定消费者组名
        DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("group1");
        // 2.指定Nameserver地址
        consumer.setNamesrvAddr("127.0.0.1:9876");
        // 设置超时
        consumer.setConsumeTimeout(15000);
        // 3.订阅主题topic和tag
        consumer.subscribe("topic1", "tag1");
        // 4.设置回调函数,处理消息
        consumer.registerMessageListener(new MessageListenerConcurrently() {
            // 接收消息内容
            @Override
            public ConsumeConcurrentlyStatus consumeMessage(List msgList, ConsumeConcurrentlyContext consumeConcurrentlyContext) {
                for (MessageExt msg:msgList) {
                    System.out.println(new String(msg.getBody()));
                }
                return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
            }
        });
        // 5.启动消费者consumer
        consumer.start();
    }
}

二、消费模式

1.负载均衡模式（默认）：消费者共同消费

MessageModel.CLUSTERING

发送10条消息

消费者1：消费了3条

消费者2：消费了5条

消费者3：消费了2条 

2.广播模式：每个消费者都消费同样的消息

MessageModel.BROADCASTING

package com.mq.rocket.consumer;

import org.apache.rocketmq.client.consumer.DefaultMQPushConsumer;
import org.apache.rocketmq.client.consumer.listener.ConsumeConcurrentlyContext;
import org.apache.rocketmq.client.consumer.listener.ConsumeConcurrentlyStatus;
import org.apache.rocketmq.client.consumer.listener.MessageListenerConcurrently;
import org.apache.rocketmq.client.exception.MQClientException;
import org.apache.rocketmq.common.message.MessageExt;
import org.apache.rocketmq.common.protocol.heartbeat.MessageModel;

import java.util.List;

/**
 * 消息接收者
 */
public class Consumer {
    public static void main(String[] args) throws MQClientException {
        // 1.创建消费者consumer，指定消费者组名
        DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("group1");
        // 2.指定Nameserver地址
        consumer.setNamesrvAddr("127.0.0.1:9876");
        // 设置超时
        consumer.setConsumeTimeout(15000);
        // 3.订阅主题topic和tag
        consumer.subscribe("topic1", "tag1");
        // 设置消费模式：负载均衡和广播模式,默认负载均衡模式-MessageModel.CLUSTERING ,广播模式-MessageModel.BROADCASTING
        consumer.setMessageModel(MessageModel.BROADCASTING);

        // 4.设置回调函数,处理消息
        consumer.registerMessageListener(new MessageListenerConcurrently() {
            // 接收消息内容
            @Override
            public ConsumeConcurrentlyStatus consumeMessage(List msgList, ConsumeConcurrentlyContext consumeConcurrentlyContext) {
                for (MessageExt msg:msgList) {
                    System.out.println(new String(msg.getBody()));
                }
                return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
            }
        });
        // 5.启动消费者consumer
        consumer.start();
    }
}