RocketMQ 顺序消费只消费一次 坑

rocketMq实现顺序消费的原理

produce在发送消息的时候，把消息发到同一个队列（queue）中,消费者注册消息监听器为MessageListenerOrderly，这样就可以保证消费端只有一个线程去消费消息

注意：是把把消息发到同一个队列（queue），不是同一个topic，默认情况下一个topic包括4个queue

单个节点（Producer端1个、Consumer端1个）

1、Producer.java 

package order;  

import java.util.List;  

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.MessageQueueSelector;
import com.alibaba.rocketmq.client.producer.SendResult;
import com.alibaba.rocketmq.common.message.Message;
import com.alibaba.rocketmq.common.message.MessageQueue;
import com.alibaba.rocketmq.remoting.exception.RemotingException;  

/**
 * Producer，发送顺序消息
 */
public class Producer {
    public static void main(String[] args) {
        try {
            DefaultMQProducer producer = new DefaultMQProducer("order_Producer");
            producer.setNamesrvAddr("192.168.100.145:9876;192.168.100.146:9876;192.168.100.149:9876;192.168.100.239:9876");  

            producer.start();  

            // String[] tags = new String[] { "TagA", "TagB", "TagC", "TagD",
            // "TagE" };  

            for (int i = 1; i <= 5; i++) {  

                Message msg = new Message("TopicOrderTest", "order_1", "KEY" + i, ("order_1 " + i).getBytes());  

                SendResult sendResult = producer.send(msg, new MessageQueueSelector() {
                    public MessageQueue select(List<MessageQueue> mqs, Message msg, Object arg) {
                        Integer id = (Integer) arg;
                        int index = id % mqs.size();
                        return mqs.get(index);
                    }
                }, 0);  

                System.out.println(sendResult);
            }  

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

2、Consumer.java   (有问题)

package order;
import java.util.List;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;
import com.alibaba.rocketmq.client.consumer.DefaultMQPushConsumer;
import com.alibaba.rocketmq.client.consumer.listener.ConsumeOrderlyContext;
import com.alibaba.rocketmq.client.consumer.listener.ConsumeOrderlyStatus;
import com.alibaba.rocketmq.client.consumer.listener.MessageListenerOrderly;
import com.alibaba.rocketmq.client.exception.MQClientException;
import com.alibaba.rocketmq.common.consumer.ConsumeFromWhere;
import com.alibaba.rocketmq.common.message.MessageExt;  

/**
 * 顺序消息消费，带事务方式（应用可控制Offset什么时候提交）
 */
public class Consumer1 {  

    public static void main(String[] args) throws MQClientException {
        DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("order_Consumer");
        consumer.setNamesrvAddr("192.168.100.145:9876;192.168.100.146:9876;192.168.100.149:9876;192.168.100.239:9876");  

        /**
         * 设置Consumer第一次启动是从队列头部开始消费还是队列尾部开始消费<br>
         * 如果非第一次启动，那么按照上次消费的位置继续消费
         */
        consumer.setConsumeFromWhere(ConsumeFromWhere.CONSUME_FROM_FIRST_OFFSET);  

        consumer.subscribe("TopicOrderTest", "*");  

        consumer.registerMessageListener(new MessageListenerOrderly() {
            AtomicLong consumeTimes = new AtomicLong(0);  

            public ConsumeOrderlyStatus consumeMessage(List<MessageExt> msgs, ConsumeOrderlyContext context) {
                // 设置自动提交
                context.setAutoCommit(true);
                for (MessageExt msg : msgs) {
                    System.out.println(msg + ",内容：" + new String(msg.getBody()));
                }  

                try {
                    TimeUnit.SECONDS.sleep(5L);
                } catch (InterruptedException e) {  

                    e.printStackTrace();
                }
                ;  

                return ConsumeOrderlyStatus.SUCCESS;
            }
        });  

        consumer.start();  

        System.out.println("Consumer1 Started.");
    }  

}

这个地方有一个大坑，注册监听类的时候，不能使用匿名内部类。不然的话，只会消费一次，然后消费者就 挂了……挂了……挂了…… 

监听类要单独写！！！

正确消费者写法：

自定义监听类：

MyMessageListener

public class MyMessageListener implements  MessageListenerOrderly {

    @Override
    public ConsumeOrderlyStatus consumeMessage(List<MessageExt> msgs, ConsumeOrderlyContext context) {
        // 设置自动提交
        context.setAutoCommit(true);
        for (MessageExt msg : msgs) {
            System.out.println(msg + ",内容：" + new String(msg.getBody()));
        }

        try {
            TimeUnit.SECONDS.sleep(5L);
        } catch (InterruptedException e) {

            e.printStackTrace();
        }

        return ConsumeOrderlyStatus.SUCCESS;
    }
}

Consumer.java

public class Consumer {

    public static void main(String[] args) throws MQClientException {
        DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("order_Consumer");
        consumer.setNamesrvAddr("101.200.33.225:9876");

        /**
         * 设置Consumer第一次启动是从队列头部开始消费还是队列尾部开始消费<br>
         * 如果非第一次启动，那么按照上次消费的位置继续消费
         */
        consumer.setConsumeFromWhere(ConsumeFromWhere.CONSUME_FROM_FIRST_OFFSET);

        consumer.subscribe("TopicOrderTest", "*");

        MyMessageListener myMessageListener = new MyMessageListener();
        consumer.registerMessageListener(myMessageListener);

        consumer.start();

        System.out.println("Consumer1 Started.");
    }
}

参考：https://www.cnblogs.com/antain/p/rocketmq.html

http://www.cnblogs.com/520playboy/p/6750023.html

http://dbaplus.cn/news-21-1123-1.html