java - RabbitMQ DefaultConsumer 导致消费者标签过多
问题描述
我有一个监听特定队列的 RabbitMQ 客户端应用程序。客户端创建 DefaultConsumer 的实例并实现 handleDelivery 方法。这是代码
protected LinkedBlockingQueue<Message> messages = new LinkedBlockingQueue<>();
public void receiveMessages() {
try {
// channel.basicQos(pollCount);
Message message = new Message();
Consumer consumer = new DefaultConsumer(channel) {
@Override
public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties, byte[] body)
throws IOException {
long deliveryTag = envelope.getDeliveryTag();
String response = new String(body, "UTF-8");
if (response != null) {
message.setId(NUID.nextGlobal());
message.setPayload(response);
message.setDeliveryTag(deliveryTag);
messages.add(message);
logger.info("Message received: ", message.getPayload());
}
}
};
logger.debug("**********Channel status: " + channel.isOpen());
channel.basicConsume(queueName, false, consumer);
} catch (Exception e) {
logger.error("Exception while getting messages from Rabbit ", e);
}
}
方法 receiveMessages() 每 500 毫秒通过一个线程频繁调用,并将消息排入不同的 List 以供使用。由于对 receiveMessages() 的投票,我观察到消费者标签在通过兔子控制台查看时不断创建和增长,如图所示。看到那些越来越多的消费者标签是正常的吗?
解决方案
我终于找到了一个可行的解决方案。正如 Luke Bakken 强调的那样,不需要投票。我现在只打电话receiveMesssages()
一次。此后,当消息发布到队列中时,我的消费者正在接收回调。
protected LinkedBlockingQueue<Message> messages = new LinkedBlockingQueue<>();
public void receiveMessages() {
try {
Message message = new Message();
DeliverCallback deliverCallback = (consumerTag, delivery) -> {
long deliveryTag = delivery.getEnvelope().getDeliveryTag();
String response = new String(delivery.getBody(), "UTF-8");
if (response != null) {
message.setId(NUID.nextGlobal());
message.setPayload(response);
message.setDeliveryTag(deliveryTag);
messages.add(message);
logger.info("Message received: ", message.getPayload());
};
channel.basicConsume(queueName, false, deliverCallback, consumerTag -> { });
} catch (Exception e) {
logger.error("Exception while getting messages from Rabbit ", e);
}
}
rabbit 控制台现在在绑定队列下仅显示 1 个消费标签条目。