RocketMQ-消费重试机制

介绍：

　　RocketMQ的消息重试及时分为两种，一种是Producer端重试，一种是Consume端重试。

　　1、Producer端重试 ：
　　　　1.1消息发没发成功，默认情况下是3次重试。
　　2、Consumer端重试：
　　　　2.1 exception的情况，一般重复16次 10s、30s、1mins、2mins、3mins等。注意reconsumeTimes这个参数；
　　　　2.2 超时情况，这种情况MQ会无限制的发送给消费端。这种情况就是Consumer端没有返回ConsumeConcurrentlyStatus.CONSUME_SUCCESS，也没有返回ConsumeConcurrentlyStatus.RECONSUME_LATER。Consumner超时的情况我们还分为一个Producer和一个Consumer的场景和一个Producer和多个Consumer（Consumer集群）的场景。下面的实例中我们会详细的做实验。

　　问题，Consumer的默认超时时间是多少？

 示例：

　　Producer端重试

　　　　producer端重试的机制比较简单，我们通过看一下源码可以发现，通过设置retryTimesWhenSendFailed定义重试次数，通过设置sendMsgTimeout来定义超时时间

producer.setRetryTimesWhenSendFailed(3); //默认是2
producer.setSendMsgTimeout(6000); //默认是3000

package org.hope.lee.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.SendCallback;
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;

public class Producer {
    public static void main(String[] args) {
        DefaultMQProducer producer = new DefaultMQProducer("push_consumer");
//        producer.setNamesrvAddr("192.168.31.176:9876");
        producer.setNamesrvAddr("192.168.31.176:9876;192.168.31.165:9876");
        try {
            // 设置实例名称
            producer.setInstanceName("quick_start_producer");
            // 设置重试次数,默认2
            producer.setRetryTimesWhenSendFailed(3);
            //设置发送超时时间，默认是3000
            producer.setSendMsgTimeout(6000);
            // 开启生产者
            producer.start();
            // 创建一条消息
            Message msg = new Message("PushTopic_tt1", "TagB", "OrderID0034", "uniform_just_for_test".getBytes());
            SendResult send = producer.send(msg);
            System.out.println("id:--->" + send.getMsgId() + ",result:--->" + send.getSendStatus());
        } catch (MQClientException e) {
            e.printStackTrace();
        } catch (RemotingException e) {
            e.printStackTrace();
        } catch (MQBrokerException e) {
            e.printStackTrace();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } 
        producer.shutdown();
    }
}

Consumer端exception的情况。

Producer端发送消息：

package org.hope.lee.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.SendCallback;
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;

public class ProducerException {
    public static void main(String[] args) {
        DefaultMQProducer producer = new DefaultMQProducer("push_consumer");
        producer.setNamesrvAddr("192.168.31.176:9876;192.168.31.165:9876");
        try {
            producer.setInstanceName("quick_start_producer");
            producer.setRetryTimesWhenSendFailed(3);
            producer.start();
            for(int i = 0; i < 10; i++) {
                Message msg = new Message("PushTopic_tt1", "TagA", "OrderID0034", ("message" + i).getBytes());
                //目前发现3.2.6版本没有这个方法，3.5.3版本有这个方法，并且必须要设置为false否则会报错
//                producer.setVipChannelEnabled(false);
                SendResult send = producer.send(msg);
                System.out.println("id:--->" + send.getMsgId() + ",result:--->" + send.getSendStatus());
            }
            
        } catch (MQClientException e) {
            e.printStackTrace();
        } catch (RemotingException e) {
            e.printStackTrace();
        } catch (MQBrokerException e) {
            e.printStackTrace();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } 
        producer.shutdown();
    }
}

Consumer端接收消息

package org.hope.lee.consumer;

import java.util.List;

import com.alibaba.rocketmq.client.consumer.DefaultMQPushConsumer;
import com.alibaba.rocketmq.client.consumer.listener.ConsumeConcurrentlyContext;
import com.alibaba.rocketmq.client.consumer.listener.ConsumeConcurrentlyStatus;
import com.alibaba.rocketmq.client.consumer.listener.MessageListener;
import com.alibaba.rocketmq.client.consumer.listener.MessageListenerConcurrently;
import com.alibaba.rocketmq.client.exception.MQClientException;
import com.alibaba.rocketmq.client.producer.DefaultMQProducer;
import com.alibaba.rocketmq.common.consumer.ConsumeFromWhere;
import com.alibaba.rocketmq.common.message.MessageExt;
import com.sun.org.apache.xpath.internal.SourceTree;

/**
 * 消费端重试的情况 :异常情况
 */
public class ConsumerException {
    public static void main(String[] args) throws MQClientException {
        DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("push_consumer");
        consumer.setNamesrvAddr("192.168.31.176:9876;192.168.31.165:9876");
        // 批量消费,每次拉取10条
        consumer.setConsumeMessageBatchMaxSize(10);// ①
        // consumer.setInstanceName("quick_start_consumer");
        // 3.2.6这个版本没有这个方法，3.5.3版本要设置这个方法为false,否则取不到topic
        // consumer.setVipChannelEnabled(false);

        // 程序第一次启动从消息队列头取数据
        // 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);
        // 订阅PushTopic下Tag为push的消息
        consumer.subscribe("PushTopic_tt1", "*");
        consumer.registerMessageListener(new MessageListenerConcurrently() {
            public ConsumeConcurrentlyStatus consumeMessage(List<MessageExt> msgs, ConsumeConcurrentlyContext context) {
                
                MessageExt msg = msgs.get(0);
                try {
                    String topic = msg.getTopic();
                    String msgBody = new String(msg.getBody(), "utf-8");
                    String tags = msg.getTags();
                    System.out.println("收到消息:topic:" + topic + ",tags:" + tags + ",msg:" + msg + "msgBody:" + msgBody);
                    if ("message4".equals(msgBody)) {
                        System.out.println("====失败消息开始=====");
                        System.out.println("msg:" + msg);
                        System.out.println("msgBody:" + msgBody);
                        System.out.println("====失败消息结束=====");
                        // 发生异常
                        int i = 1 / 0;
                        System.out.println(i);
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                    // ②如果重试了三次就返回成功
                    if (msg.getReconsumeTimes() == 3) {
                        return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
                    }
                    return ConsumeConcurrentlyStatus.RECONSUME_LATER;
                }

                return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
            }
        });
        consumer.start();
        System.out.println("Consumer Started.");
        // consumer.suspend();

    }
}

 我们先启动ConsumerException再启动ProducerException。我们看到在①处发生了异常，这个时候消息就会进行重试，我们看看Consumer端的输出来分析一下。

Consumer Started.
收到消息:topic:PushTopic_tt1,tags:TagA,msg:MessageExt [queueId=0, storeSize=149, queueOffset=4, sysFlag=0, bornTimestamp=1515158266232, bornHost=/192.168.31.38:7309, storeTimestamp=1515158293401, storeHost=/192.168.31.176:10911, msgId=C0A81FB000002A9F0000000000001603, commitLogOffset=5635, bodyCRC=886509244, reconsumeTimes=0, preparedTransactionOffset=0, toString()=Message [topic=PushTopic_tt1, flag=0, properties={TAGS=TagA, KEYS=OrderID0034, WAIT=true, MAX_OFFSET=5, MIN_OFFSET=0}, body=8]]msgBody:message0
收到消息:topic:PushTopic_tt1,tags:TagA,msg:MessageExt [queueId=1, storeSize=149, queueOffset=3, sysFlag=0, bornTimestamp=1515158266249, bornHost=/192.168.31.38:7309, storeTimestamp=1515158293411, storeHost=/192.168.31.176:10911, msgId=C0A81FB000002A9F0000000000001698, commitLogOffset=5784, bodyCRC=1137720874, reconsumeTimes=0, preparedTransactionOffset=0, toString()=Message [topic=PushTopic_tt1, flag=0, properties={TAGS=TagA, KEYS=OrderID0034, WAIT=true, MAX_OFFSET=4, MIN_OFFSET=0}, body=8]]msgBody:message1
收到消息:topic:PushTopic_tt1,tags:TagA,msg:MessageExt [queueId=3, storeSize=149, queueOffset=2, sysFlag=0, bornTimestamp=1515158266267, bornHost=/192.168.31.38:7309, storeTimestamp=1515158293428, storeHost=/192.168.31.176:10911, msgId=C0A81FB000002A9F00000000000017C2, commitLogOffset=6082, bodyCRC=769548038, reconsumeTimes=0, preparedTransactionOffset=0, toString()=Message [topic=PushTopic_tt1, flag=0, properties={TAGS=TagA, KEYS=OrderID0034, WAIT=true, MAX_OFFSET=3, MIN_OFFSET=0}, body=8]]msgBody:message3
收到消息:topic:PushTopic_tt1,tags:TagA,msg:MessageExt [queueId=2, storeSize=149, queueOffset=2, sysFlag=0, bornTimestamp=1515158266259, bornHost=/192.168.31.38:7309, storeTimestamp=1515158293420, storeHost=/192.168.31.176:10911, msgId=C0A81FB000002A9F000000000000172D, commitLogOffset=5933, bodyCRC=1524199312, reconsumeTimes=0, preparedTransactionOffset=0, toString()=Message [topic=PushTopic_tt1, flag=0, properties={TAGS=TagA, KEYS=OrderID0034, WAIT=true, MAX_OFFSET=3, MIN_OFFSET=0}, body=8]]msgBody:message2
收到消息:topic:PushTopic_tt1,tags:TagA,msg:MessageExt [queueId=0, storeSize=149, queueOffset=5, sysFlag=0, bornTimestamp=1515158266276, bornHost=/192.168.31.38:7309, storeTimestamp=1515158293445, storeHost=/192.168.31.176:10911, msgId=C0A81FB000002A9F0000000000001857, commitLogOffset=6231, bodyCRC=867879589, reconsumeTimes=0, preparedTransactionOffset=0, toString()=Message [topic=PushTopic_tt1, flag=0, properties={TAGS=TagA, KEYS=OrderID0034, WAIT=true, MAX_OFFSET=6, MIN_OFFSET=0}, body=8]]msgBody:message4
====失败消息开始=====
msg:MessageExt [queueId=0, storeSize=149, queueOffset=5, sysFlag=0, bornTimestamp=1515158266276, bornHost=/192.168.31.38:7309, storeTimestamp=1515158293445, storeHost=/192.168.31.176:10911, msgId=C0A81FB000002A9F0000000000001857, commitLogOffset=6231, bodyCRC=867879589, reconsumeTimes=0, preparedTransactionOffset=0, toString()=Message [topic=PushTopic_tt1, flag=0, properties={TAGS=TagA, KEYS=OrderID0034, WAIT=true, MAX_OFFSET=6, MIN_OFFSET=0}, body=8]]
msgBody:message4
====失败消息结束=====
java.lang.ArithmeticException: / by zero
    at org.hope.lee.consumer.ConsumerException$1.consumeMessage(ConsumerException.java:55)
    at com.alibaba.rocketmq.client.impl.consumer.ConsumeMessageConcurrentlyService$ConsumeRequest.run(ConsumeMessageConcurrentlyService.java:142)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
    at java.util.concurrent.FutureTask.run(FutureTask.java:166)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:722)
收到消息:topic:PushTopic_tt1,tags:TagA,msg:MessageExt [queueId=1, storeSize=149, queueOffset=4, sysFlag=0, bornTimestamp=1515158266292, bornHost=/192.168.31.38:7309, storeTimestamp=1515158293452, storeHost=/192.168.31.176:10911, msgId=C0A81FB000002A9F00000000000018EC, commitLogOffset=6380, bodyCRC=1153301043, reconsumeTimes=0, preparedTransactionOffset=0, toString()=Message [topic=PushTopic_tt1, flag=0, properties={TAGS=TagA, KEYS=OrderID0034, WAIT=true, MAX_OFFSET=5, MIN_OFFSET=0}, body=8]]msgBody:message5
收到消息:topic:PushTopic_tt1,tags:TagA,msg:MessageExt [queueId=2, storeSize=149, queueOffset=3, sysFlag=0, bornTimestamp=1515158266300, bornHost=/192.168.31.38:7309, storeTimestamp=1515158293482, storeHost=/192.168.31.176:10911, msgId=C0A81FB000002A9F0000000000001A9D, commitLogOffset=6813, bodyCRC=1572121481, reconsumeTimes=0, preparedTransactionOffset=0, toString()=Message [topic=PushTopic_tt1, flag=0, properties={TAGS=TagA, KEYS=OrderID0034, WAIT=true, MAX_OFFSET=4, MIN_OFFSET=0}, body=8]]msgBody:message6
收到消息:topic:PushTopic_tt1,tags:TagA,msg:MessageExt [queueId=3, storeSize=149, queueOffset=3, sysFlag=0, bornTimestamp=1515158266328, bornHost=/192.168.31.38:7309, storeTimestamp=1515158293491, storeHost=/192.168.31.176:10911, msgId=C0A81FB000002A9F0000000000001B32, commitLogOffset=6962, bodyCRC=716413727, reconsumeTimes=0, preparedTransactionOffset=0, toString()=Message [topic=PushTopic_tt1, flag=0, properties={TAGS=TagA, KEYS=OrderID0034, WAIT=true, MAX_OFFSET=4, MIN_OFFSET=0}, body=8]]msgBody:message7
收到消息:topic:PushTopic_tt1,tags:TagA,msg:MessageExt [queueId=0, storeSize=149, queueOffset=6, sysFlag=0, bornTimestamp=1515158266337, bornHost=/192.168.31.38:7309, storeTimestamp=1515158293497, storeHost=/192.168.31.176:10911, msgId=C0A81FB000002A9F0000000000001BC7, commitLogOffset=7111, bodyCRC=973899406, reconsumeTimes=0, preparedTransactionOffset=0, toString()=Message [topic=PushTopic_tt1, flag=0, properties={TAGS=TagA, KEYS=OrderID0034, WAIT=true, MAX_OFFSET=7, MIN_OFFSET=0}, body=8]]msgBody:message8
收到消息:topic:PushTopic_tt1,tags:TagA,msg:MessageExt [queueId=1, storeSize=149, queueOffset=5, sysFlag=0, bornTimestamp=1515158266348, bornHost=/192.168.31.38:7309, storeTimestamp=1515158293508, storeHost=/192.168.31.176:10911, msgId=C0A81FB000002A9F0000000000001C5C, commitLogOffset=7260, bodyCRC=1292613144, reconsumeTimes=0, preparedTransactionOffset=0, toString()=Message [topic=PushTopic_tt1, flag=0, properties={TAGS=TagA, KEYS=OrderID0034, WAIT=true, MAX_OFFSET=6, MIN_OFFSET=0}, body=8]]msgBody:message9
收到消息:topic:PushTopic_tt1,tags:TagA,msg:MessageExt [queueId=0, storeSize=285, queueOffset=7, sysFlag=0, bornTimestamp=1515158266276, bornHost=/192.168.31.38:7309, storeTimestamp=1515158303482, storeHost=/192.168.31.176:10911, msgId=C0A81FB000002A9F0000000000001CF1, commitLogOffset=7409, bodyCRC=867879589, reconsumeTimes=1, preparedTransactionOffset=0, toString()=Message [topic=PushTopic_tt1, flag=0, properties={DELAY=3, ORIGIN_MESSAGE_ID=C0A81FB000002A9F0000000000001857, REAL_TOPIC=%RETRY%push_consumer, TAGS=TagA, WAIT=false, KEYS=OrderID0034, RETRY_TOPIC=PushTopic_tt1, MAX_OFFSET=8, MIN_OFFSET=0, REAL_QID=0}, body=8]]msgBody:message4
====失败消息开始=====
msg:MessageExt [queueId=0, storeSize=285, queueOffset=7, sysFlag=0, bornTimestamp=1515158266276, bornHost=/192.168.31.38:7309, storeTimestamp=1515158303482, storeHost=/192.168.31.176:10911, msgId=C0A81FB000002A9F0000000000001CF1, commitLogOffset=7409, bodyCRC=867879589, reconsumeTimes=1, preparedTransactionOffset=0, toString()=Message [topic=PushTopic_tt1, flag=0, properties={DELAY=3, ORIGIN_MESSAGE_ID=C0A81FB000002A9F0000000000001857, REAL_TOPIC=%RETRY%push_consumer, TAGS=TagA, WAIT=false, KEYS=OrderID0034, RETRY_TOPIC=PushTopic_tt1, MAX_OFFSET=8, MIN_OFFSET=0, REAL_QID=0}, body=8]]
msgBody:message4
====失败消息结束=====
java.lang.ArithmeticException: / by zero
    at org.hope.lee.consumer.ConsumerException$1.consumeMessage(ConsumerException.java:55)
    at com.alibaba.rocketmq.client.impl.consumer.ConsumeMessageConcurrentlyService$ConsumeRequest.run(ConsumeMessageConcurrentlyService.java:142)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
    at java.util.concurrent.FutureTask.run(FutureTask.java:166)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:722)
收到消息:topic:PushTopic_tt1,tags:TagA,msg:MessageExt [queueId=0, storeSize=285, queueOffset=8, sysFlag=0, bornTimestamp=1515158266276, bornHost=/192.168.31.38:7309, storeTimestamp=1515158333701, storeHost=/192.168.31.176:10911, msgId=C0A81FB000002A9F0000000000001F2A, commitLogOffset=7978, bodyCRC=867879589, reconsumeTimes=2, preparedTransactionOffset=0, toString()=Message [topic=PushTopic_tt1, flag=0, properties={DELAY=4, ORIGIN_MESSAGE_ID=C0A81FB000002A9F0000000000001857, REAL_TOPIC=%RETRY%push_consumer, TAGS=TagA, WAIT=false, KEYS=OrderID0034, RETRY_TOPIC=PushTopic_tt1, MAX_OFFSET=9, MIN_OFFSET=0, REAL_QID=0}, body=8]]msgBody:message4
====失败消息开始=====
msg:MessageExt [queueId=0, storeSize=285, queueOffset=8, sysFlag=0, bornTimestamp=1515158266276, bornHost=/192.168.31.38:7309, storeTimestamp=1515158333701, storeHost=/192.168.31.176:10911, msgId=C0A81FB000002A9F0000000000001F2A, commitLogOffset=7978, bodyCRC=867879589, reconsumeTimes=2, preparedTransactionOffset=0, toString()=Message [topic=PushTopic_tt1, flag=0, properties={DELAY=4, ORIGIN_MESSAGE_ID=C0A81FB000002A9F0000000000001857, REAL_TOPIC=%RETRY%push_consumer, TAGS=TagA, WAIT=false, KEYS=OrderID0034, RETRY_TOPIC=PushTopic_tt1, MAX_OFFSET=9, MIN_OFFSET=0, REAL_QID=0}, body=8]]
msgBody:message4
====失败消息结束=====
java.lang.ArithmeticException: / by zero
    at org.hope.lee.consumer.ConsumerException$1.consumeMessage(ConsumerException.java:55)
    at com.alibaba.rocketmq.client.impl.consumer.ConsumeMessageConcurrentlyService$ConsumeRequest.run(ConsumeMessageConcurrentlyService.java:142)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
    at java.util.concurrent.FutureTask.run(FutureTask.java:166)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:722)
收到消息:topic:PushTopic_tt1,tags:TagA,msg:MessageExt [queueId=0, storeSize=285, queueOffset=9, sysFlag=0, bornTimestamp=1515158266276, bornHost=/192.168.31.38:7309, storeTimestamp=1515158394718, storeHost=/192.168.31.176:10911, msgId=C0A81FB000002A9F0000000000002163, commitLogOffset=8547, bodyCRC=867879589, reconsumeTimes=3, preparedTransactionOffset=0, toString()=Message [topic=PushTopic_tt1, flag=0, properties={DELAY=5, ORIGIN_MESSAGE_ID=C0A81FB000002A9F0000000000001857, REAL_TOPIC=%RETRY%push_consumer, TAGS=TagA, WAIT=false, KEYS=OrderID0034, RETRY_TOPIC=PushTopic_tt1, MAX_OFFSET=10, MIN_OFFSET=0, REAL_QID=0}, body=8]]msgBody:message4
====失败消息开始=====
msg:MessageExt [queueId=0, storeSize=285, queueOffset=9, sysFlag=0, bornTimestamp=1515158266276, bornHost=/192.168.31.38:7309, storeTimestamp=1515158394718, storeHost=/192.168.31.176:10911, msgId=C0A81FB000002A9F0000000000002163, commitLogOffset=8547, bodyCRC=867879589, reconsumeTimes=3, preparedTransactionOffset=0, toString()=Message [topic=PushTopic_tt1, flag=0, properties={DELAY=5, ORIGIN_MESSAGE_ID=C0A81FB000002A9F0000000000001857, REAL_TOPIC=%RETRY%push_consumer, TAGS=TagA, WAIT=false, KEYS=OrderID0034, RETRY_TOPIC=PushTopic_tt1, MAX_OFFSET=10, MIN_OFFSET=0, REAL_QID=0}, body=8]]
msgBody:message4
====失败消息结束=====
java.lang.ArithmeticException: / by zero
    at org.hope.lee.consumer.ConsumerException$1.consumeMessage(ConsumerException.java:55)
    at com.alibaba.rocketmq.client.impl.consumer.ConsumeMessageConcurrentlyService$ConsumeRequest.run(ConsumeMessageConcurrentlyService.java:142)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
    at java.util.concurrent.FutureTask.run(FutureTask.java:166)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:722)
收到消息:topic:PushTopic_tt1,tags:TagA,msg:MessageExt [queueId=0, storeSize=285, queueOffset=10, sysFlag=0, bornTimestamp=1515158266276, bornHost=/192.168.31.38:7309, storeTimestamp=1515158514742, storeHost=/192.168.31.176:10911, msgId=C0A81FB000002A9F000000000000239C, commitLogOffset=9116, bodyCRC=867879589, reconsumeTimes=4, preparedTransactionOffset=0, toString()=Message [topic=PushTopic_tt1, flag=0, properties={DELAY=6, ORIGIN_MESSAGE_ID=C0A81FB000002A9F0000000000001857, REAL_TOPIC=%RETRY%push_consumer, TAGS=TagA, WAIT=false, KEYS=OrderID0034, RETRY_TOPIC=PushTopic_tt1, MAX_OFFSET=11, MIN_OFFSET=0, REAL_QID=0}, body=8]]msgBody:message4
====失败消息开始=====
msg:MessageExt [queueId=0, storeSize=285, queueOffset=10, sysFlag=0, bornTimestamp=1515158266276, bornHost=/192.168.31.38:7309, storeTimestamp=1515158514742, storeHost=/192.168.31.176:10911, msgId=C0A81FB000002A9F000000000000239C, commitLogOffset=9116, bodyCRC=867879589, reconsumeTimes=4, preparedTransactionOffset=0, toString()=Message [topic=PushTopic_tt1, flag=0, properties={DELAY=6, ORIGIN_MESSAGE_ID=C0A81FB000002A9F0000000000001857, REAL_TOPIC=%RETRY%push_consumer, TAGS=TagA, WAIT=false, KEYS=OrderID0034, RETRY_TOPIC=PushTopic_tt1, MAX_OFFSET=11, MIN_OFFSET=0, REAL_QID=0}, body=8]]
msgBody:message4
====失败消息结束=====
java.lang.ArithmeticException: / by zero
    at org.hope.lee.consumer.ConsumerException$1.consumeMessage(ConsumerException.java:55)
    at com.alibaba.rocketmq.client.impl.consumer.ConsumeMessageConcurrentlyService$ConsumeRequest.run(ConsumeMessageConcurrentlyService.java:142)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
    at java.util.concurrent.FutureTask.run(FutureTask.java:166)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:722)
java.lang.ArithmeticException: / by zero
    at org.hope.lee.consumer.ConsumerException$1.consumeMessage(ConsumerException.java:55)
    at com.alibaba.rocketmq.client.impl.consumer.ConsumeMessageConcurrentlyService$ConsumeRequest.run(ConsumeMessageConcurrentlyService.java:142)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
    at java.util.concurrent.FutureTask.run(FutureTask.java:166)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:722)

 　　我们看到最初消费到第四条数据的时候抛出异常，然后继续消费了剩下的6条消息，过了一段时间MQ又重试发送消息给Consumer端，又抛出异常，过一段时间MQ还是会发送消息过来。我么恩看一下用蓝色标注的字体，这个就是记录重试次数的字段。我们可以利用这个字段进行业务逻辑处理，比如重试了3次就返回SUCCESS了，就不再重试了。比如Consumern代码中的②处

 　customer端发生超时的情况讨论。

　　在消费端，我们有两个Consumer来组成一个集群。ConsumerClusterMember1中我们设置一个Thread.sleep()来模拟一个消费超时的状态。

　　实验的步骤如下：

　　一、先启动ConsumerClusterMember1

　　二、再启动ConsumerClusterMember2。

　　三、然后启动ProducerCluster来发送一条消息。

　　四、这个时候ConsumerClusterMember1可能会先接收到这条消息，然后sleep等待了。这个时候我们停掉它的JVM

　　五、过了一段时间，ConsumerClusterMember2就会重新收到Producer端发过来的消息。完成了Consumer端集群的消息超时。

　　下面我们看看代码

Produder端：

package org.hope.lee.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.SendCallback;
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;
/**
 * 配合ConsumerClusterMember1,2做测试
 */
public class ProducerCluster {
    public static void main(String[] args) {
        DefaultMQProducer producer = new DefaultMQProducer("producer_cluster");
        producer.setNamesrvAddr("192.168.31.176:9876;192.168.31.165:9876");
        try {
            // 设置实例名称
            producer.setInstanceName("producer_cluster_name");
            // 开启生产者
            producer.start();
            // 创建一条消息
            Message msg = new Message("cluster_timeout_test", "TagA", "OrderID0034", "customer_cluster_test".getBytes());
            SendResult send = producer.send(msg);
            System.out.println("id:--->" + send.getMsgId() + ",result:--->" + send.getSendStatus());
        } catch (MQClientException e) {
            e.printStackTrace();
        } catch (RemotingException e) {
            e.printStackTrace();
        } catch (MQBrokerException e) {
            e.printStackTrace();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } 
        producer.shutdown();
    }
}

消费端集群：

package org.hope.lee.consumer;

import java.util.List;

import com.alibaba.rocketmq.client.consumer.DefaultMQPushConsumer;
import com.alibaba.rocketmq.client.consumer.listener.ConsumeConcurrentlyContext;
import com.alibaba.rocketmq.client.consumer.listener.ConsumeConcurrentlyStatus;
import com.alibaba.rocketmq.client.consumer.listener.MessageListenerConcurrently;
import com.alibaba.rocketmq.client.exception.MQClientException;
import com.alibaba.rocketmq.common.consumer.ConsumeFromWhere;
import com.alibaba.rocketmq.common.message.MessageExt;

public class ConsumerClusterMember1 {
    public static void main(String[] args) throws MQClientException {
        DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("consumer_cluster");
        consumer.setNamesrvAddr("192.168.31.176:9876;192.168.31.165:9876");
        // 批量消费,每次拉取10条
        consumer.setConsumeMessageBatchMaxSize(10);
        // 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);
        // 订阅PushTopic下Tag为push的消息
        consumer.subscribe("cluster_timeout_test", "TagA || Tag B || Tage C");
        consumer.registerMessageListener(new MqMessageListener1());
        consumer.start();
        System.out.println("Consumer Started.");

    }
}
class MqMessageListener1 implements MessageListenerConcurrently{
    public ConsumeConcurrentlyStatus consumeMessage(List<MessageExt> msgs, ConsumeConcurrentlyContext context) {
        try {
            MessageExt msg = msgs.get(0);
            System.out.println("------消息处理中--------");
            Thread.sleep(60000);
            String msgBody = new String(msg.getBody(), "utf-8");
            System.out.println("msgBody:" + msgBody);
        } catch(Exception e) {
            e.printStackTrace();
            return ConsumeConcurrentlyStatus.RECONSUME_LATER;
        }
        return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
    }
    
}

package org.hope.lee.consumer;

import java.util.List;

import com.alibaba.rocketmq.client.consumer.DefaultMQPushConsumer;
import com.alibaba.rocketmq.client.consumer.listener.ConsumeConcurrentlyContext;
import com.alibaba.rocketmq.client.consumer.listener.ConsumeConcurrentlyStatus;
import com.alibaba.rocketmq.client.consumer.listener.MessageListenerConcurrently;
import com.alibaba.rocketmq.client.exception.MQClientException;
import com.alibaba.rocketmq.common.consumer.ConsumeFromWhere;
import com.alibaba.rocketmq.common.message.MessageExt;

public class ConsumerClusterMember2 {
    public static void main(String[] args) throws MQClientException {
        DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("consumer_cluster");
        consumer.setNamesrvAddr("192.168.31.176:9876;192.168.31.165:9876");
        // 批量消费,每次拉取10条
        consumer.setConsumeMessageBatchMaxSize(10);
        // 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);
        // 订阅PushTopic下Tag为push的消息
        consumer.subscribe("cluster_timeout_test", "TagA || Tag B || Tage C");
        consumer.registerMessageListener(new MqMessageListener2());
        consumer.start();
        System.out.println("Consumer Started.");

    }
}

class MqMessageListener2 implements MessageListenerConcurrently{
    public ConsumeConcurrentlyStatus consumeMessage(List<MessageExt> msgs, ConsumeConcurrentlyContext context) {
        try {
            MessageExt msg = msgs.get(0);
            String msgBody = new String(msg.getBody(), "utf-8");
            System.out.println("msgBody:" + msgBody);
        } catch(Exception e) {
            e.printStackTrace();
            return ConsumeConcurrentlyStatus.RECONSUME_LATER;
        }
        return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
    }
    
}

https://gitee.com/huayicompany/RocketMQ-learn/tree/master/rocketmq-api

参考：

[1]博客，http://blog.csdn.net/u010634288/article/details/56049305