要实现AMQP（RabbitMQ）具有集群客户端的发布/订阅，可以使用RabbitMQ的Java客户端库。下面是一个简单的代码示例：

import com.rabbitmq.client.*;

import java.io.IOException;

public class Publisher {
    private static final String EXCHANGE_NAME = "my_exchange";
    private static final String QUEUE_NAME = "my_queue";
    private static final String ROUTING_KEY = "my_routing_key";

    public static void main(String[] args) throws Exception {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        factory.setPort(5672);
        factory.setUsername("guest");
        factory.setPassword("guest");

        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();

        channel.exchangeDeclare(EXCHANGE_NAME, BuiltinExchangeType.FANOUT);
        channel.queueDeclare(QUEUE_NAME, true, false, false, null);
        channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, ROUTING_KEY);

        String message = "Hello, World!";
        channel.basicPublish(EXCHANGE_NAME, ROUTING_KEY, null, message.getBytes("UTF-8"));

        System.out.println("Message sent: " + message);

        channel.close();
        connection.close();
    }
}

import com.rabbitmq.client.*;

import java.io.IOException;

public class Subscriber {
    private static final String EXCHANGE_NAME = "my_exchange";
    private static final String QUEUE_NAME = "my_queue";
    private static final String ROUTING_KEY = "my_routing_key";

    public static void main(String[] args) throws Exception {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        factory.setPort(5672);
        factory.setUsername("guest");
        factory.setPassword("guest");

        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();

        channel.exchangeDeclare(EXCHANGE_NAME, BuiltinExchangeType.FANOUT);
        channel.queueDeclare(QUEUE_NAME, true, false, false, null);
        channel.queueBind(QUEUE_NAME, EXCHANGE_NAME, ROUTING_KEY);

        Consumer consumer = new DefaultConsumer(channel) {
            @Override
            public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body) throws IOException {
                String message = new String(body, "UTF-8");
                System.out.println("Received message: " + message);
            }
        };

        channel.basicConsume(QUEUE_NAME, true, consumer);
    }
}

在这个示例中，发布者（Publisher）将消息发送到特定的交换机（Exchange）和路由键（Routing Key），然后订阅者（Subscriber）从队列中接收消息。通过使用相同的交换机和队列，多个订阅者可以在一个集群中同时接收消息。

请注意，你需要替换示例中的主机名、端口号、用户名和密码，以便与你的RabbitMQ集群配置匹配。