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Preface

Tips ： The following is the main body of this article , The following cases can be used for reference

One 、 Send a normal message

import com.aliyun.openservices.ons.api.Message;
    import com.aliyun.openservices.ons.api.Producer;
    import com.aliyun.openservices.ons.api.SendResult;
    import com.aliyun.openservices.ons.api.ONSFactory;
    import com.aliyun.openservices.ons.api.PropertyKeyConst;

    import java.util.Properties;

    public class ProducerTest {
    
        public static void main(String[] args) {
    
            Properties properties = new Properties();
            // AccessKeyId  Alicloud Authentication , Get the information from Alibaba cloud user information management console .
            properties.put(PropertyKeyConst.AccessKey,"XXX");
            // AccessKeySecret  Alicloud Authentication , Get the information from Alibaba cloud user information management console .
            properties.put(PropertyKeyConst.SecretKey, "XXX");
            // Set send timeout , Company ： millisecond .
            properties.setProperty(PropertyKeyConst.SendMsgTimeoutMillis, "3000");
            //  Set up TCP Access domain name , Enter the message queue RocketMQ View in the access point area of the console instance details page .
            properties.put(PropertyKeyConst.NAMESRV_ADDR, "XXX");
            Producer producer = ONSFactory.createProducer(properties);
            //  Before sending a message , Must call start Method to start Producer, Just one call .
            producer.start();

            // Loop messages .
            for (int i = 0; i < 100; i++){
    
                Message msg = new Message( 
                    //  Ordinary messages belong to Topic, Do not use the of ordinary messages Topic To send and receive other types of messages .
                    "TopicTestMQ",
                    // Message Tag Can be understood as Gmail The label in , Recategorize messages , convenient Consumer Specify filter conditions in message queue RocketMQ Version of server filtering .
                    "TagA",
                    // Message Body It can be any binary form of data , Message queue RocketMQ The version does not do any intervention .
                    //  need Producer And Consumer Agree on a consistent way to serialize and deserialize .
                    "Hello MQ".getBytes());
                //  Set the business critical properties that represent the message , Please be as global and unique as possible .
                //  In order to facilitate you to receive messages in the case of normal , It can be through message queue RocketMQ The version console queries the message and reissues it .
                //  Be careful ： No setting will not affect the normal sending and receiving of messages .
                msg.setKey("ORDERID_" + i);

                try {
    
                    SendResult sendResult = producer.send(msg);
                    //  Synchronous messaging , As long as we don't throw exceptions, we will succeed .
                    if (sendResult != null) {
    
                        System.out.println(new Date() + " Send mq message success. Topic is:" + msg.getTopic() + " msgId is: " + sendResult.getMessageId());
                    }
                }
                catch (Exception e) {
    
                    //  Message delivery failed , Need to retry processing , You can resend the message or persist the data for compensation processing .
                    System.out.println(new Date() + " Send mq message failed. Topic is:" + msg.getTopic());
                    e.printStackTrace();
                }
            }

            //  Before the app exits , The destruction Producer object .
            //  Be careful ： If you don't destroy it, there's no problem .
            producer.shutdown();
        }
    }               

Two 、 Subscribe to general news

Subscription mode
Message queue RocketMQ Version supports the following two subscription methods ：

Cluster subscription
The same Group ID All marked Consumer Average share of consumption news . For example, a Topic Yes 9 Bar message , One Group ID Yes 3 individual Consumer example , Then, in the cluster consumption mode, each instance is allocated equally , Consume only... Of them 3 Bar message . The settings are as follows .
// Cluster subscription mode settings （ Without setting , The default is cluster subscription mode ）.
properties.put(PropertyKeyConst.MessageModel, PropertyValueConst.CLUSTERING);
Broadcast subscription
The same Group ID All marked Consumer They will each consume a message once . For example, a Topic Yes 9 Bar message , One Group ID Yes 3 individual Consumer example , Then in the broadcast consumption mode, each instance will consume its own 9 Bar message . The settings are as follows .
// Broadcast subscription mode settings .
properties.put(PropertyKeyConst.MessageModel, PropertyValueConst.BROADCASTING);

Message queue RocketMQ Version supports the following two message acquisition methods ：
Push： The message is sent by the message queue RocketMQ Push version to Consumer.Push Under way , Message queue RocketMQ The version also supports batch consumption , Batch messages can be uniformly pushed to Consumer Consumption .
Pull： Message by Consumer Active from message queue RocketMQ Plate pulling .

Here we show only Push Send message by

import com.aliyun.openservices.ons.api.Action;
import com.aliyun.openservices.ons.api.ConsumeContext;
import com.aliyun.openservices.ons.api.Consumer;
import com.aliyun.openservices.ons.api.Message;
import com.aliyun.openservices.ons.api.MessageListener;
import com.aliyun.openservices.ons.api.ONSFactory;
import com.aliyun.openservices.ons.api.PropertyKeyConst;

import java.util.Properties;

public class ConsumerTest {
    
   public static void main(String[] args) {
    
       Properties properties = new Properties();
        //  You created Group ID.
       properties.put(PropertyKeyConst.GROUP_ID, "XXX");
        // AccessKey ID Alicloud Authentication , In Ali cloud RAM Console creation .
       properties.put(PropertyKeyConst.AccessKey, "XXX");
        // Accesskey Secret Alicloud Authentication , In Alibaba cloud service RAM Console creation .
       properties.put(PropertyKeyConst.SecretKey, "XXX");
        //  Set up TCP Access domain name , Enter the instance details page of the console TCP Protocol client access point area view .
       properties.put(PropertyKeyConst.NAMESRV_ADDR, "XXX");
          //  Subscription cluster mode ( Default ).
          // properties.put(PropertyKeyConst.MessageModel, PropertyValueConst.CLUSTERING);
          //  Broadcast subscription mode .
          // properties.put(PropertyKeyConst.MessageModel, PropertyValueConst.BROADCASTING);

       Consumer consumer = ONSFactory.createConsumer(properties);
       consumer.subscribe("TopicTestMQ", "TagA||TagB", new MessageListener() {
     // Subscribe to multiple Tag.
           public Action consume(Message message, ConsumeContext context) {
    
               System.out.println("Receive: " + message);
               return Action.CommitMessage;
           }
       });

        // Subscribe to another Topic, To unsubscribe from this Topic, Please delete the subscription code in this section , Restart the consumer .
        consumer.subscribe("TopicTestMQ-Other", "*", new MessageListener() {
     // Subscribe to all Tag.
           public Action consume(Message message, ConsumeContext context) {
    
               System.out.println("Receive: " + message);
               return Action.CommitMessage;
           }
       });

       consumer.start();
       System.out.println("Consumer Started");
   }
}            

summary