前言

提示：以下是本篇文章正文内容，下面案例可供参考

一、发送普通消息（同步发送方式）

准备环境

开源的Java客户端支持连接分布式消息服务RocketMQ版，推荐使用的客户端版本为4.9.0。

通过以下方式引入依赖：
使用Maven方式引入依赖。

<dependency>
    <groupId>org.apache.rocketmq</groupId>
    <artifactId>rocketmq-client</artifactId>
    <version>4.9.0</version>
</dependency>

示例

同步发送是指消息发送方发出一条消息到服务端，服务端接收并处理消息，然后返回响应给发送方，发送方收到响应后才会发送下一条消息的通讯方式。

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 Main {
    public static void main(String[] args) {
        DefaultMQProducer producer = new DefaultMQProducer("ProducerGroupName");
        //填入元数据连接地址
        producer.setNamesrvAddr("192.168.0.1:8100");
        try {
            producer.start();
            Message msg = new Message("TopicTest",
                "TagA",
                "OrderID188",
                "Hello world".getBytes(RemotingHelper.DEFAULT_CHARSET));
            SendResult sendResult = producer.send(msg);
            System.out.printf("%s%n", sendResult);

        } catch (Exception e) {
            e.printStackTrace();

        }
        producer.shutdown();
    }
}

二、订阅普通消息

import java.util.List;
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.consumer.ConsumeFromWhere;
import org.apache.rocketmq.common.message.MessageExt;

public class PushConsumer {

    public static void main(String[] args) throws InterruptedException, MQClientException {
        DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("CID_JODIE_1");
        //填入元数据连接地址
        consumer.setNamesrvAddr("192.168.0.1:8100");
        consumer.subscribe("TopicTest", "*");
        consumer.registerMessageListener(new MessageListenerConcurrently() {
            @Override
            public ConsumeConcurrentlyStatus consumeMessage(List<MessageExt> msgs, ConsumeConcurrentlyContext context) {
                System.out.printf("%s Receive New Messages: %s %n", Thread.currentThread().getName(), msgs);
                return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
            }
        });
        consumer.start();
        System.out.printf("Consumer Started.%n");
    }
}

三、使用ACL权限访问

使用Maven方式引入依赖。

<dependency>
    <groupId>org.apache.rocketmq</groupId>
    <artifactId>rocketmq-client</artifactId>
    <version>4.9.0</version>
</dependency>

生产者增加用户认证信息
生产者初始化时需要增加“rpcHook”参数。

RPCHook rpcHook = new AclClientRPCHook(new SessionCredentials(ACL_ACCESS_KEY, ACL_SECRET_KEY));
DefaultMQProducer producer = new DefaultMQProducer("ProducerGroupName", rpcHook);

ACL_ACCESS_KEY为用户名，ACL_SECRET_KEY为用户的密钥。

消费者增加用户认证信息
消费者初始化时需要增加“rpcHook”参数。

RPCHook rpcHook = new AclClientRPCHook(new SessionCredentials(ACL_ACCESS_KEY, ACL_SECRET_KEY));
DefaultMQPushConsumer consumer = new DefaultMQPushConsumer(null, "ConsumerGroupName", rpcHook);