RocketMq消息处理

顺序消费

消息有序指的是可以按照消息的发送顺序来消费(FIFO)。RocketMQ可以严格的保证消息有序，可以分为分区有序或者全局有序。

顺序消费的原理解析，在默认的情况下消息发送会采取Round Robin轮询方式把消息发送到不同的queue(分区队列)；而消费消息的时候从多个queue上拉取消息，这种情况发送和消费是不能保证顺序。但是如果控制发送的顺序消息只依次发送到同一个queue中，消费的时候只从这个queue上依次拉取，则就保证了顺序。当发送和消费参与的queue只有一个，则是全局有序；如果多个queue参与，则为分区有序，即相对每个queue，消息都是有序的。

下面用订单进行分区有序的示例。一个订单的顺序流程是：创建、付款、推送、完成。订单号相同的消息会被先后发送到同一个队列中，消费时，同一个OrderId获取到的肯定是同一个队列。

示例：

生产者

import org.apache.rocketmq.client.producer.DefaultMQProducer;
import org.apache.rocketmq.client.producer.MessageQueueSelector;
import org.apache.rocketmq.client.producer.SendResult;
import org.apache.rocketmq.common.message.Message;
import org.apache.rocketmq.common.message.MessageQueue;

import java.util.List;

public class Producer {

    public static void main(String[] args) throws Exception {
        // 创建消息生产者producer，并制定生产者组名
        DefaultMQProducer producer = new DefaultMQProducer("order-producer-group1");
        // 指定Nameserver地址
        producer.setNamesrvAddr("xxx.xxx.xxx.xxx:9876");
        // 启动producer
        producer.start();
        // 构建消息集合
        List<OrderStep> orderSteps = OrderStep.buildOrders();
        // 发送消息
        for (int i = 0; i < orderSteps.size(); i++) {
            String body = orderSteps.get(i) + "";
            Message message = new Message("OrderTopic", "Order", "i" + i, body.getBytes());
            /**
             * 参数一：消息对象
             * 参数二：消息队列的选择器
             * 参数三：选择队列的业务标识（订单ID）
             */
            SendResult sendResult = producer.send(message, new MessageQueueSelector() {
                /**
                 *
                 * @param mqs：队列集合
                 * @param msg：消息对象
                 * @param arg：业务标识的参数
                 * @return
                 */
                @Override
                public MessageQueue select(List<MessageQueue> mqs, Message msg, Object arg) {
                    long orderId = (long) arg;
                    long index = orderId % mqs.size();
                    return mqs.get((int) index);
                }
            }, orderSteps.get(i).getOrderId());

            System.out.println("发送结果：" + sendResult);
        }
        producer.shutdown();
    }

}
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消费者

import org.apache.rocketmq.client.consumer.DefaultMQPushConsumer;
import org.apache.rocketmq.client.consumer.listener.ConsumeOrderlyContext;
import org.apache.rocketmq.client.consumer.listener.ConsumeOrderlyStatus;
import org.apache.rocketmq.client.consumer.listener.MessageListenerOrderly;
import org.apache.rocketmq.client.exception.MQClientException;
import org.apache.rocketmq.common.message.MessageExt;

import java.util.List;

public class Consumer {
    public static void main(String[] args) throws MQClientException {
        //1.创建消费者Consumer，制定消费者组名
        DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("order-consumer-group1");
        //2.指定Nameserver地址
        consumer.setNamesrvAddr("xxx.xxx.xxx.xxx:9876");
        //3.订阅主题Topic和Tag
        consumer.subscribe("OrderTopic", "*");

        //4.注册消息监听器
        consumer.registerMessageListener(new MessageListenerOrderly() {

            @Override
            public ConsumeOrderlyStatus consumeMessage(List<MessageExt> msgs, ConsumeOrderlyContext context) {
                for (MessageExt msg : msgs) {
                    System.out.println("线程名称：【" + Thread.currentThread().getName() + "】:" + new String(msg.getBody()));
                }
                return ConsumeOrderlyStatus.SUCCESS;
            }
        });
        //5.启动消费者
        consumer.start();
        System.out.println("消费者启动");
    }
}
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订单实体

import java.util.ArrayList;
import java.util.List;

/**
 * 订单构建者
 */
public class OrderStep {
    private long orderId;
    private String desc;

    public long getOrderId() {
        return orderId;
    }

    public void setOrderId(long orderId) {
        this.orderId = orderId;
    }

    public String getDesc() {
        return desc;
    }

    public void setDesc(String desc) {
        this.desc = desc;
    }

    @Override
    public String toString() {
        return "OrderStep{" +
                "orderId=" + orderId +
                ", desc='" + desc + "'" +
                "}";
    }

    public static List<OrderStep> buildOrders() {
        //  1039L   : 创建    付款 推送 完成
        //  1065L   ： 创建   付款
        //  7235L   ：创建    付款
        List<OrderStep> orderList = new ArrayList<OrderStep>();

        OrderStep orderDemo = new OrderStep();
        orderDemo.setOrderId(1039L);
        orderDemo.setDesc("创建");
        orderList.add(orderDemo);

        orderDemo = new OrderStep();
        orderDemo.setOrderId(1065L);
        orderDemo.setDesc("创建");
        orderList.add(orderDemo);

        orderDemo = new OrderStep();
        orderDemo.setOrderId(1039L);
        orderDemo.setDesc("付款");
        orderList.add(orderDemo);

        orderDemo = new OrderStep();
        orderDemo.setOrderId(7235L);
        orderDemo.setDesc("创建");
        orderList.add(orderDemo);

        orderDemo = new OrderStep();
        orderDemo.setOrderId(1065L);
        orderDemo.setDesc("付款");
        orderList.add(orderDemo);

        orderDemo = new OrderStep();
        orderDemo.setOrderId(7235L);
        orderDemo.setDesc("付款");
        orderList.add(orderDemo);

        orderDemo = new OrderStep();
        orderDemo.setOrderId(1065L);
        orderDemo.setDesc("完成");
        orderList.add(orderDemo);

        orderDemo = new OrderStep();
        orderDemo.setOrderId(1039L);
        orderDemo.setDesc("推送");
        orderList.add(orderDemo);

        orderDemo = new OrderStep();
        orderDemo.setOrderId(7235L);
        orderDemo.setDesc("完成");
        orderList.add(orderDemo);

        orderDemo = new OrderStep();
        orderDemo.setOrderId(1039L);
        orderDemo.setDesc("完成");
        orderList.add(orderDemo);

        return orderList;
    }
}
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广播

广播消费方式：向主题的所有订阅者发送消息。如果您希望所有订阅者都收到有关某个主题的消息，广播是一个不错的选择。

集群消费方式：不同的消费组可以消费同一主题的同一个消息，但是一个消费组的多个消费者只能共同消费一次消息。

生产者：

import org.apache.rocketmq.client.producer.DefaultMQProducer;
import org.apache.rocketmq.client.producer.SendResult;
import org.apache.rocketmq.common.message.Message;
import org.apache.rocketmq.remoting.common.RemotingHelper;

public class BroadcastProducer {
    public static void main(String[] args) throws Exception {
        DefaultMQProducer producer = new DefaultMQProducer("Broadcast-Producer-Group");

        // Specify name server addresses.
        producer.setNamesrvAddr("xxx.xxx.xxx.xxx:9876");

        producer.start();

        for (int i = 0; i < 10; i++){
            Message msg = new Message("TopicTest",
                "TagA",
                "OrderID188",
                "Hello world".getBytes(RemotingHelper.DEFAULT_CHARSET));
            SendResult sendResult = producer.send(msg);
            System.out.printf("%s%n", sendResult);
        }
        producer.shutdown();
    }
}
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消费者1：

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.common.consumer.ConsumeFromWhere;
import org.apache.rocketmq.common.message.MessageExt;
import org.apache.rocketmq.common.protocol.heartbeat.MessageModel;

import java.util.List;

public class BroadcastConsumer1 {
    public static void main(String[] args) throws Exception {
        DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("Broadcast-Consumer-group");

        // Specify name server addresses.
        consumer.setNamesrvAddr("xxx.xxx.xxx.xxx:9876");

        consumer.setConsumeFromWhere(ConsumeFromWhere.CONSUME_FROM_FIRST_OFFSET);

        //set to broadcast mode
        consumer.setMessageModel(MessageModel.BROADCASTING);

        consumer.subscribe("TopicTest", "TagA");

        consumer.registerMessageListener(new MessageListenerConcurrently() {

            @Override
            public ConsumeConcurrentlyStatus consumeMessage(List<MessageExt> msgs,
                                                            ConsumeConcurrentlyContext context) {
                System.out.printf(Thread.currentThread().getName() + " Receive New Messages: " + msgs + "%n");
                return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
            }
        });

        consumer.start();
        System.out.printf("Broadcast Consumer Started.%n");
    }
}
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消费者2：

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.common.consumer.ConsumeFromWhere;
import org.apache.rocketmq.common.message.MessageExt;
import org.apache.rocketmq.common.protocol.heartbeat.MessageModel;

import java.util.List;

public class BroadcastConsumer2 {
    public static void main(String[] args) throws Exception {
        DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("Broadcast-Consumer-group");

        // Specify name server addresses.
        consumer.setNamesrvAddr("xxx.xxx.xxx.xxx:9876");

        consumer.setConsumeFromWhere(ConsumeFromWhere.CONSUME_FROM_FIRST_OFFSET);

        //set to broadcast mode
        consumer.setMessageModel(MessageModel.BROADCASTING);

        consumer.subscribe("TopicTest", "TagA");

        consumer.registerMessageListener(new MessageListenerConcurrently() {

            @Override
            public ConsumeConcurrentlyStatus consumeMessage(List<MessageExt> msgs,
                                                            ConsumeConcurrentlyContext context) {
                System.out.printf(Thread.currentThread().getName() + " Receive New Messages: " + msgs + "%n");
                return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
            }
        });

        consumer.start();
        System.out.printf("Broadcast Consumer Started.%n");
    }
}
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定时消费

预定消息：预定消息与普通消息的不同之处在于，它们直到指定的时间之后才会被传递。

消费者：

import org.apache.rocketmq.client.producer.DefaultMQProducer;
import org.apache.rocketmq.client.producer.SendResult;
import org.apache.rocketmq.common.message.Message;

public class ScheduledMessageProducer {

    public static void main(String[] args) throws Exception {
        // Instantiate a producer to send scheduled messages
        DefaultMQProducer producer = new DefaultMQProducer("Scheduled-Producer-Group");
        //2.指定Nameserver地址
        producer.setNamesrvAddr("xxx.xxx.xxx.xxx:9876");
        // Launch producer
        producer.start();
        int totalMessagesToSend = 10;
        for (int i = 0; i < totalMessagesToSend; i++) {
            Message message = new Message("TestTopic", ("Hello scheduled message " + i).getBytes());
            // This message will be delivered to consumer 10 seconds later.
            // delayTimeLevel 默认延迟等级 : 1s 5s 10s 30s 1m 2m 3m 4m 5m 6m 7m 8m 9m 10m 20m 30m 1h 2h， 传入1代表1s, 2代表5s, 以此类推
            message.setDelayTimeLevel(3);
            // Send the message
            SendResult sendResult = producer.send(message);
            System.out.println("发送结果：" + sendResult + ".time:" + System.currentTimeMillis());
        }

        // Shutdown producer after use.
        producer.shutdown();
    }

}
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消费者：

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.common.message.MessageExt;
 import java.util.List;
    
 public class ScheduledMessageConsumer {
    
     public static void main(String[] args) throws Exception {
         // Instantiate message consumer
         DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("Scheduled-Consumer-Group");
         //2.指定Nameserver地址
         consumer.setNamesrvAddr("xxx.xxx.xxx.xxx:9876");
         // Subscribe topics
         consumer.subscribe("TestTopic", "*");
         // Register message listener
         consumer.registerMessageListener(new MessageListenerConcurrently() {
             @Override
             public ConsumeConcurrentlyStatus consumeMessage(List<MessageExt> messages, ConsumeConcurrentlyContext context) {
                 for (MessageExt message : messages) {
                     // Print approximate delay time period
                     System.out.println("Receive message[msgId=" + message.getMsgId() + "] ["+System.currentTimeMillis()+"--"+message.getStoreTimestamp()+"]"
                             + (System.currentTimeMillis() - message.getStoreTimestamp()) + "ms later");
                 }
                 return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
             }
         });
         // Launch consumer
         consumer.start();
     }
 }
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批量消息

批量发送消息：提高了传递小消息的性能。

批量发送消息使用限制：同一批次的消息应该具有：相同的主题，相同的waitStoreMsgOK 并且没有调度支持。此外，一批消息的总大小不应超过 1M。

如果你一次只发送不超过1M的消息，使用批处理很容易

生产者：

import org.apache.rocketmq.client.producer.DefaultMQProducer;
import org.apache.rocketmq.client.producer.SendResult;
import org.apache.rocketmq.client.producer.SendStatus;
import org.apache.rocketmq.common.message.Message;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.TimeUnit;

public class Producer {

    public static void main(String[] args) throws Exception {
        //1.创建消息生产者producer，并制定生产者组名
        DefaultMQProducer producer = new DefaultMQProducer("group1");
        //2.指定Nameserver地址
        producer.setNamesrvAddr("xxx.xxx.xxx.xxx:9876");
        //3.启动producer
        producer.start();
        List<Message> msgs = new ArrayList<Message>();
        //4.创建消息对象，指定主题Topic、Tag和消息体
        /**
         * 参数一：消息主题Topic
         * 参数二：消息Tag
         * 参数三：消息内容
         */
        Message msg1 = new Message("BatchTopic", "Tag1", ("Hello World" + 1).getBytes());
        Message msg2 = new Message("BatchTopic", "Tag1", ("Hello World" + 2).getBytes());
        Message msg3 = new Message("BatchTopic", "Tag1", ("Hello World" + 3).getBytes());

        msgs.add(msg1);
        msgs.add(msg2);
        msgs.add(msg3);

        //5.发送消息
        SendResult result = producer.send(msgs);
        //发送状态
        SendStatus status = result.getSendStatus();
        System.out.println("发送结果:" + result);
        //线程睡1秒
        TimeUnit.SECONDS.sleep(1);
        //6.关闭生产者producer
        producer.shutdown();
    }

}
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消费者：

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.common.message.MessageExt;

import java.util.List;

public class Consumer {
    public static void main(String[] args) throws Exception {
        //1.创建消费者Consumer，制定消费者组名
        DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("group1");
        //2.指定Nameserver地址
        consumer.setNamesrvAddr("xxx.xxx.xxx.xxx:9876");
        //3.订阅主题Topic和Tag
        consumer.subscribe("BatchTopic", "*");

        //4.设置回调函数，处理消息
        consumer.registerMessageListener(new MessageListenerConcurrently() {

            //接受消息内容
            @Override
            public ConsumeConcurrentlyStatus consumeMessage(List<MessageExt> msgs, ConsumeConcurrentlyContext context) {
                for (MessageExt msg : msgs) {
                    System.out.println("consumeThread=" + Thread.currentThread().getName() + "," + new String(msg.getBody()));
                }
                return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
            }
        });
        //5.启动消费者consumer
        consumer.start();

        System.out.println("消费者启动");
    }
}
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发送大批量时，并且可能不确定它是否超过了大小限制。这时候，最好拆分一下列表

public class ListSplitter implements Iterator<List<Message>> {
    private final int SIZE_LIMIT = 1000 * 1000;
    private final List<Message> messages;
    private int currIndex;
    public ListSplitter(List<Message> messages) {
            this.messages = messages;
    }
    @Override public boolean hasNext() {
        return currIndex < messages.size();
    }
    @Override public List<Message> next() {
        int nextIndex = currIndex;
        int totalSize = 0;
        for (; nextIndex < messages.size(); nextIndex++) {
            Message message = messages.get(nextIndex);
            int tmpSize = message.getTopic().length() + message.getBody().length;
            Map<String, String> properties = message.getProperties();
            for (Map.Entry<String, String> entry : properties.entrySet()) {
                tmpSize += entry.getKey().length() + entry.getValue().length();
            }
            tmpSize = tmpSize + 20; //for log overhead
            if (tmpSize > SIZE_LIMIT) {
                //it is unexpected that single message exceeds the SIZE_LIMIT
                //here just let it go, otherwise it will block the splitting process
                if (nextIndex - currIndex == 0) {
                   //if the next sublist has no element, add this one and then break, otherwise just break
                   nextIndex++;  
                }
                break;
            }
            if (tmpSize + totalSize > SIZE_LIMIT) {
                break;
            } else {
                totalSize += tmpSize;
            }
    
        }
        List<Message> subList = messages.subList(currIndex, nextIndex);
        currIndex = nextIndex;
        return subList;
    }
}
//then you could split the large list into small ones:
ListSplitter splitter = new ListSplitter(messages);
while (splitter.hasNext()) {
   try {
       List<Message>  listItem = splitter.next();
       producer.send(listItem);
   } catch (Exception e) {
       e.printStackTrace();
       //handle the error
   }
}
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过滤器过滤消息

在大多数情况下，标签是一种简单而有用的设计，用于选择您想要的消息。例如：

DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("CID_EXAMPLE");
consumer.subscribe("TOPIC", "TAGA || TAGB || TAGC");
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消费者将收到包含 TAGA 或 TAGB 或 TAGC 的消息。但限制是一条消息只能有一个标签，这可能不适用于复杂的场景。在这种情况下，您可以使用 SQL 表达式来过滤消息。

RocketMQ 只定义了一些基本的语法来支持这个特性。您也可以轻松扩展它。

数值比较，如>, >=, <, <=, BETWEEN, =;
字符比较，如=, <>, IN;
IS NULL或IS NOT NULL;
逻辑AND, OR, NOT;

常量类型有：

数字，如 123、3.1415；
字符，如 'abc'，必须用单引号引起；
NULL，特殊常数；
布尔值，TRUE或FALSE；

生产者：

import org.apache.rocketmq.client.producer.DefaultMQProducer;
import org.apache.rocketmq.client.producer.SendResult;
import org.apache.rocketmq.client.producer.SendStatus;
import org.apache.rocketmq.common.message.Message;

import java.util.concurrent.TimeUnit;

public class Producer {

    public static void main(String[] args) throws Exception {
        //1.创建消息生产者producer，并制定生产者组名
        DefaultMQProducer producer = new DefaultMQProducer("group1");
        //2.指定Nameserver地址
        producer.setNamesrvAddr("xxx.xxx.xxx.xxx:9876");
        //3.启动producer
        producer.start();

        for (int i = 0; i < 10; i++) {
            //4.创建消息对象，指定主题Topic、Tag和消息体
            /**
             * 参数一：消息主题Topic
             * 参数二：消息Tag
             * 参数三：消息内容
             */
            Message msg = new Message("FilterSQLTopic", "Tag1", ("Hello World" + i).getBytes());

            msg.putUserProperty("i", String.valueOf(i));

            //5.发送消息
            SendResult result = producer.send(msg);
            //发送状态
            SendStatus status = result.getSendStatus();

            System.out.println("发送结果:" + result);

            //线程睡1秒
            TimeUnit.SECONDS.sleep(2);
        }

        //6.关闭生产者producer
        producer.shutdown();
    }

}
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消费者：

import org.apache.rocketmq.client.consumer.DefaultMQPushConsumer;
import org.apache.rocketmq.client.consumer.MessageSelector;
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.common.message.MessageExt;

import java.util.List;

public class Consumer {
    public static void main(String[] args) throws Exception {
        //1.创建消费者Consumer，制定消费者组名
        DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("group1");
        //2.指定Nameserver地址
        consumer.setNamesrvAddr("xxx.xxx.xxx.xxx:9876");
        //3.订阅主题Topic和Tag
        consumer.subscribe("FilterSQLTopic", MessageSelector.bySql("i>5"));

        //4.设置回调函数，处理消息
        consumer.registerMessageListener(new MessageListenerConcurrently() {

            //接受消息内容
            @Override
            public ConsumeConcurrentlyStatus consumeMessage(List<MessageExt> msgs, ConsumeConcurrentlyContext context) {
                for (MessageExt msg : msgs) {
                    System.out.println("consumeThread=" + Thread.currentThread().getName() + "," + new String(msg.getBody()));
                }
                return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
            }
        });
        //5.启动消费者consumer
        consumer.start();
        System.out.println("消费者启动");
    }
}
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事务消息

事务性消息：它可以被认为是两阶段提交消息的实现，以确保分布式系统中的最终一致性。事务性消息确保本地事务的执行和消息的发送可以原子地执行。

事务消息有三种状态：

TransactionStatus.CommitTransaction：提交事务，表示允许消费者消费这条消息。
TransactionStatus.RollbackTransaction：回滚事务，表示消息将被删除，不允许消费。
TransactionStatus.Unknown：中间状态，表示需要MQ回查来确定状态。

生产者：

import org.apache.commons.lang3.StringUtils;
import org.apache.rocketmq.client.producer.*;
import org.apache.rocketmq.common.message.Message;
import org.apache.rocketmq.common.message.MessageExt;

import java.util.concurrent.TimeUnit;

/**
 * 发送同步消息
 */
public class Producer {

    public static void main(String[] args) throws Exception {
        //1.创建消息生产者producer，并制定生产者组名
        TransactionMQProducer producer = new TransactionMQProducer("group5");
        //2.指定Nameserver地址
        producer.setNamesrvAddr("xxx.xxx.xxx.xxx:9876");

        //添加事务监听器
        producer.setTransactionListener(new TransactionListener() {
            /**
             * 在该方法中执行本地事务
             * @param msg
             * @param arg
             * @return
             */
            @Override
            public LocalTransactionState executeLocalTransaction(Message msg, Object arg) {
                System.out.println("-消息的Tag:" + msg.getTags());
                if (StringUtils.equals("TAGA", msg.getTags())) {
                    return LocalTransactionState.COMMIT_MESSAGE;
                } else if (StringUtils.equals("TAGB", msg.getTags())) {
                    return LocalTransactionState.ROLLBACK_MESSAGE;
                } else if (StringUtils.equals("TAGC", msg.getTags())) {
                    return LocalTransactionState.UNKNOW;
                }
                return LocalTransactionState.UNKNOW;
            }

            /**
             * 该方法时MQ进行消息事务状态回查
             * @param msg
             * @return
             */
            @Override
            public LocalTransactionState checkLocalTransaction(MessageExt msg) {
                System.out.println("消息的Tag:" + msg.getTags());
                return LocalTransactionState.COMMIT_MESSAGE;
            }
        });

        //3.启动producer
        producer.start();

        String[] tags = {"TAGA", "TAGB", "TAGC"};

        for (int i = 0; i < 3; i++) {
            //4.创建消息对象，指定主题Topic、Tag和消息体
            /**
             * 参数一：消息主题Topic
             * 参数二：消息Tag
             * 参数三：消息内容
             */
            Message msg = new Message("TransactionTopic", tags[i], ("Hello World" + i).getBytes());
            //5.发送消息
            SendResult result = producer.sendMessageInTransaction(msg, null);
            //发送状态
            SendStatus status = result.getSendStatus();

            System.out.println("发送结果:" + result);

            //线程睡1秒
            TimeUnit.SECONDS.sleep(2);
        }

        //6.关闭生产者producer
        //producer.shutdown();
    }
}
复制代码

消费者：

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.common.message.MessageExt;

import java.util.List;

/**
 * 消息的接受者
 */
public class Consumer {

    public static void main(String[] args) throws Exception {
        //1.创建消费者Consumer，制定消费者组名
        DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("group1");
        //2.指定Nameserver地址
        consumer.setNamesrvAddr("xxx.xxx.xxx.xxx:9876");
        //3.订阅主题Topic和Tag
        consumer.subscribe("TransactionTopic", "*");

        //4.设置回调函数，处理消息
        consumer.registerMessageListener(new MessageListenerConcurrently() {
            //接受消息内容
            @Override
            public ConsumeConcurrentlyStatus consumeMessage(List<MessageExt> msgs, ConsumeConcurrentlyContext context) {
                for (MessageExt msg : msgs) {
                    System.out.println("consumeThread=" + Thread.currentThread().getName() + "," + new String(msg.getBody()));
                }
                return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
            }
        });
        //5.启动消费者consumer
        consumer.start();
        System.out.println("生产者启动");
    }
}
复制代码

参考文档：rocketmq.apache.org/docs/broadc…

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