java rabbitmq 暂停恢复订阅代码

以下是 Java 中 RabbitMQ 暂停和恢复订阅的示例代码：

import com.rabbitmq.client.*;

import java.io.IOException;
import java.util.concurrent.TimeoutException;

public class Consumer {

    private final static String QUEUE_NAME = "hello";

    public static void main(String[] args) throws IOException, TimeoutException {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        try (Connection connection = factory.newConnection();
             Channel channel = connection.createChannel()) {
            channel.queueDeclare(QUEUE_NAME, false, false, false, null);

            // 创建消费者
            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 + "'");
                }
            };

            // 启动消费者
            String consumerTag = channel.basicConsume(QUEUE_NAME, true, consumer);

            // 暂停订阅
            channel.basicCancel(consumerTag);

            // 重新订阅
            channel.basicConsume(QUEUE_NAME, true, consumer);
        }
    }
}

在上面的示例代码中，首先创建了一个消费者并启动订阅。然后通过调用 `basicCancel` 方法暂停订阅，再通过重新调用 `basicConsume` 方法恢复订阅，以实现暂停和恢复订阅的功能。