关于java:使用RocketMQ消费消息

RocketMQ 生产端

明天要来跟大家学习怎么应用 RocketMQ 来进行音讯的生产

先简略创立个 Maven 我的项目应用

• 增加依赖

<dependency>
    <groupId>org.apache.rocketmq</groupId>
    <artifactId>rocketmq-client</artifactId>
    <version>4.9.2</version>
</dependency>

• 启动消费者

  package mq.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;
  
  public class BroadcastConsumer {public static void main(String[] args) throws MQClientException {
          // 创立一个 push 模式的生产组
          DefaultMQPushConsumer pushConsumer = new DefaultMQPushConsumer("pushConsumer");
          pushConsumer.setNamesrvAddr("localhost:9876");
          // 集群模式
          pushConsumer.setMessageModel(MessageModel.CLUSTERING);
          //  订阅的 topic tag
          pushConsumer.subscribe("topic_test01","Tag1 || Tag2");
  
          pushConsumer.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;
              }
          });
          pushConsumer.start();
          System.out.printf("Broadcast Consumer Started.%n");
  
      }
  

• 启动生产者

  package mq.producer;
  
  import org.apache.rocketmq.client.exception.MQBrokerException;
  import org.apache.rocketmq.client.exception.MQClientException;
  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;
  import org.apache.rocketmq.remoting.exception.RemotingException;
  
  import java.io.UnsupportedEncodingException;
  
  public class SyncProducerV2 {
      /**
       * 同步音讯发送
       *
       * @param args
       * @throws MQClientException
       * @throws MQBrokerException
       * @throws RemotingException
       * @throws InterruptedException
       * @throws UnsupportedEncodingException
       */
      public static void main(String[] args) throws MQClientException, MQBrokerException, RemotingException, InterruptedException, UnsupportedEncodingException {System.out.println("SyncProducer start......");
          DefaultMQProducer defaultMQProducer = new DefaultMQProducer("pg_sync_01");
          defaultMQProducer.setNamesrvAddr("localhost:9876");
          defaultMQProducer.start();
          for (int i = 0; i < 10; i++) {send(defaultMQProducer, i, i % 3);
          }
          defaultMQProducer.shutdown();
          System.out.println("SyncProducer end......");
  
      }
  
      private static void send(DefaultMQProducer defaultMQProducer, Integer i, int tag) throws MQClientException, RemotingException, MQBrokerException, InterruptedException, UnsupportedEncodingException {SendResult sendResult = defaultMQProducer.send(new Message("topic_test01", "Tag" + tag, ("hello this is sync message_" + i + "!").getBytes(RemotingHelper.DEFAULT_CHARSET)));
          System.out.println(sendResult);
      }
  }

• 消费者生产

能够看到生产了 Tag 为 Tag1、Tag2 的音讯

其它 Tag 会被过滤掉

生产分类

RocketMQ 的生产模式分为两种：BROADCASTING（播送）和CLUSTERING（集群）

那这两种模式有什么区别呢？

• 播送：雷同生产组下的实例会反复生产同一个 Topic 的音讯，能够了解为大家做同样的工作，生产进度存储在客户端，有可能会导致局部音讯没有被生产
• 集群：雷同生产组下的实例会负载平衡地生产同一个 Topic 的音讯，能够了解为分工合作，生产进度存储在 Broker 端

所以大部分零碎都会应用集群模式去生产信息，毕竟能够程度拓展消费者来接受更大的生产压力

播送模式相对来说应用比拟少，个别都是一些音讯告诉同步的场景，想同步刷新缓存等

本文由博客一文多发平台 OpenWrite 公布！