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当有多个消费者都在同一个队列中拿取消息时，会轮询从队列中拿取消息消费。

RabbitMQUtil类为工具类，获取Channel。

import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;public class RabbitMQUtil {public static Channel getChannel() throws Exception {//得到工厂ConnectionFactory factory = new ConnectionFactory();factory.setHost("localhost");factory.setUsername("guest");factory.setPassword("guest");//生成连接Connection connection = factory.newConnection();//获取信道return connection.createChannel();}
}

1. 创建一个生产者，并启动

import com.rabbitmq.client.Channel;import java.util.Scanner;public class Producer {private final static String QUEUE_NAME = "hello";public static void main(String[] args) throws Exception {Channel channel = RabbitMQUtil.getChannel();channel.queueDeclare(QUEUE_NAME, false, false, false, null);Scanner sc = new Scanner(System.in);while (sc.hasNext()) {String message = sc.next();channel.basicPublish("", QUEUE_NAME, null, message.getBytes());}}
}

2. 创建两个消费者，并启动

import com.rabbitmq.client.CancelCallback;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.DeliverCallback;public class Consumer1 {private final static String QUEUE_NAME = "hello";public static void main(String[] args) throws Exception {Channel channel = RabbitMQUtil.getChannel();DeliverCallback deliverCallback = (consumerTag, message) -> {System.out.println("接收到信息：" + new String(message.getBody()));};CancelCallback cancelCallback = consumerTag -> {System.out.println("消息消费被中断");};System.out.println("C1消费者启动等待消费......");channel.basicConsume(QUEUE_NAME, true, deliverCallback, cancelCallback);}
}

import com.rabbitmq.client.CancelCallback;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.DeliverCallback;public class Consumer2 {private final static String QUEUE_NAME = "hello";public static void main(String[] args) throws Exception {Channel channel = RabbitMQUtil.getChannel();DeliverCallback deliverCallback = (consumerTag, message) -> {System.out.println("接收到信息：" + new String(message.getBody()));};CancelCallback cancelCallback = consumerTag -> {System.out.println("消息消费被中断");};System.out.println("C2消费者启动等待消费......");channel.basicConsume(QUEUE_NAME, true, deliverCallback, cancelCallback);}
}

3. 运行结果图如下。可以看到两个消费者轮流从队列中拿取消息消费。