写三个rocketmq消费者代码

好的，以下是三个RocketMQ消费者的示例代码：

1. 基本的RocketMQ消费者示例代码：

import org.apache.rocketmq.client.consumer.DefaultMQPushConsumer;
import org.apache.rocketmq.client.exception.MQClientException;
import org.apache.rocketmq.client.consumer.listener.ConsumeConcurrentlyContext;
import org.apache.rocketmq.client.consumer.listener.MessageListenerConcurrently;
import org.apache.rocketmq.common.message.MessageExt;
import java.util.List;

public class BasicRocketMQConsumer {
    public static void main(String[] args) throws InterruptedException, MQClientException {
        // 实例化消费者
        DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("group_name");

        // 设置NameServer的地址
        consumer.setNamesrvAddr("localhost:9876");

        // 订阅一个Topic下的所有消息
        consumer.subscribe("TopicTest", "*");

        // 注册回调函数，处理消息
        consumer.registerMessageListener(new MessageListenerConcurrently() {
            @Override
            public ConsumeConcurrentlyStatus consumeMessage(List<MessageExt> msgs, ConsumeConcurrentlyContext context) {
                for (MessageExt msg : msgs) {
                    System.out.println("Receive message: " + new String(msg.getBody()));
                }
                return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
            }
        });

        // 启动消费者实例
        consumer.start();

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

2. RocketMQ消费者使用负载均衡模式示例代码：

import org.apache.rocketmq.client.consumer.DefaultMQPushConsumer;
import org.apache.rocketmq.client.consumer.listener.ConsumeConcurrentlyContext;
import org.apache.rocketmq.client.consumer.listener.MessageListenerConcurrently;
import org.apache.rocketmq.common.message.MessageExt;
import org.apache.rocketmq.common.protocol.heartbeat.MessageModel;
import java.util.List;

public class LoadBalanceRocketMQConsumer {
    public static void main(String[] args) throws Exception {
        // 实例化消费者
        DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("group_name");

        // 设置NameServer的地址
        consumer.setNamesrvAddr("localhost:9876");

        // 订阅TopicTest这个Topic下的所有消息
        consumer.subscribe("TopicTest", "*");

        // 设置消费模式为负载均衡模式
        consumer.setMessageModel(MessageModel.CLUSTERING);

        // 注册回调函数，处理消息
        consumer.registerMessageListener(new MessageListenerConcurrently() {
            @Override
            public ConsumeConcurrentlyStatus consumeMessage(List<MessageExt> msgs, ConsumeConcurrentlyContext context) {
                for (MessageExt msg : msgs) {
                    System.out.println("Receive message: " + new String(msg.getBody()));
                }
                return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
            }
        });

        // 启动消费者实例
        consumer.start();

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

3. RocketMQ消费者使用广播模式示例代码：

import org.apache.rocketmq.client.consumer.DefaultMQPushConsumer;
import org.apache.rocketmq.client.consumer.listener.ConsumeConcurrentlyContext;
import org.apache.rocketmq.client.consumer.listener.MessageListenerConcurrently;
import org.apache.rocketmq.common.message.MessageExt;
import org.apache.rocketmq.common.protocol.heartbeat.MessageModel;
import java.util.List;

public class BroadcastRocketMQConsumer {
    public static void main(String[] args) throws Exception {
        // 实例化消费者
        DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("group_name");

        // 设置NameServer的地址
        consumer.setNamesrvAddr("localhost:9876");

        // 订阅TopicTest这个Topic下的所有消息
        consumer.subscribe("TopicTest", "*");

        // 设置消费模式为广播模式
        consumer.setMessageModel(MessageModel.BROADCASTING);

        // 注册回调函数，处理消息
        consumer.registerMessageListener(new MessageListenerConcurrently() {
            @Override
            public ConsumeConcurrentlyStatus consumeMessage(List<MessageExt> msgs, ConsumeConcurrentlyContext context) {
                for (MessageExt msg : msgs) {
                    System.out.println("Receive message: " + new String(msg.getBody()));
                }
                return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
            }
        });

        // 启动消费者实例
        consumer.start();

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

以上示例代码是使用Apache RocketMQ的Java客户端实现的消费者，可以根据需要修改相应的参数和逻辑进行使用。