Java 消息数超过并发使用者数后，使用者未分配给消息

我想了解一旦消息被消费，消费者是如何为并发消费者工作的。消费者bean是被丢弃并创建新的还是被重用？我可以看到在RabbitMQ服务器设置之后，当我发送消息时，消费者bean被实例化

我的问题是，一旦消息的数量等于并发使用者的数量，消息侦听器中的使用者对于下一条消息将为null。我可以在日志中看到以前消息的Ack/Nack，预回迁设置为1

XML配置：

消费者代码如下所示：

@EnableRabbit
@Service 
public class RabbitMQListener implements MessageListener {
    @Autowired
    private ApplicationContext applicationContext;

    protected static Logger logger = LoggerFactory.getLogger(RabbitMQListener.class);

    private TaskExecutor taskExecutor;
    private RabbitSender responseSender;
    private String consumerType;
    private String encoding;

     public TaskExecutor getTaskExecutor() {
        return taskExecutor;
    }

    public void setTaskExecutor(TaskExecutor taskExecutor) {
        this.taskExecutor = taskExecutor;
    }

    public void setResponseSender(RabbitSender responseSender) {
        this.responseSender = responseSender;
    }

    public void setConsumerType(String consumerType) {
        this.consumerType = consumerType;
    }

    public void setEncoding(String encoding) {
        this.encoding = encoding;
    }

    @Override
    @RabbitListener(containerFactory = Constants.CONTAINER_FACTORY, queues = "#{'${QM_QUEUES}'.split(',')}")
    public void onMessage(final Message arg0) {

        if (arg0 != null) {
            try {
                String message = new String(arg0.getBody());
                logger.info("Message Properties class: " + arg0.getClass());
                logger.info("Message Properties: " + arg0.getMessageProperties());
                logger.info("Received message for consumer: " + this.consumerType);
                logger.info("Message :: " + message);
                Object bean = applicationContext.getBean(this.consumerType);
                if (bean instanceof Consumer) {
                    logger.debug("Processing message for consumer: " + this.consumerType);
                    Consumer consumer = (Consumer)bean;
                    consumer.setMessage(message);
                    consumer.setResponseSender(responseSender);
                    logger.debug("Executing consumer: " + this.consumerType);
                    taskExecutor.execute(consumer);
                } else {
                    logger.info("Could not process message due to invalid consumer.");
                }

            } 
            catch (AmqpException e1) {
                logger.error("Spring AMQP error processing message.", e1.getMessage());
            }
            catch (Exception e2) {
                logger.error("General error processing message.", e2.getMessage());
            }
        }
        else {
            logger.debug("message received is NULL");
        }

    }


}

---

所描述的行为与收到消息后不确认消息一致。RabbitMQ可以在传递时配置为消息。如果未发生这种情况，或者未配置，RabbitMQ将假定使用者正忙，并且不会向其发送其他消息。您必须在成功处理消息后发送

ack

，才能接收队列中的下一条消息

不，消费者不会被丢弃，它会持续运行。你的问题不清楚；您所说的

是什么意思？对于下一条消息，消息侦听器中的消费者为空。

？编辑问题以使其更清晰，并显示您的代码和配置。我已编辑问题以提供更多信息。我的问题是，我只能为simplemessagelistenercontainer中定义的ConcurrentConsumer数量调用正确/适当的consumer。例如，如果我的concurrentconsumers在该队列中设置为4到4条消息，则正确调用了consumer（如日志中所示）。消费者的第5条信息变为空。仍然不清楚；您需要显示为消费者记录已接收消息的代码：XYZConsumer——因为

springListenerContainerRABC

只有一个

rabbitMessageListenerRABC

，所以您根本不清楚在原型范围

XYZConsumer

bean中要实现什么。还不清楚为什么您有一个容器工厂和一个容器。@GaryRussell容器工厂（SimpleRabbit）用于建立连接和侦听队列中的消息。侦听器容器（SimpleMessageListenerContainer）用于将传入消息转发给相应的使用者。我在上面添加了消费者代码。因为springListenerContainerRABC只有一个rabbitMessageListenerRABC：我有多个容器，每个容器触发各自的消费者bean。这是一个非常奇怪的体系结构。为每条消息创建一个新的bean实例是非常低效的。然而，由于rabbitMessageListenerRABC是一个单例；尚不清楚如何将

this.consumerType

重置为

null

，因此发生了其他事情。最后，在不同的线程上运行消费者是不明智的；如果出现故障，您可能会丢失消息。

00:17:49.725 [springListenerContainerRABC-1] INFO RabbitMQListener - **Received message for consumer: XYZConsumer**

00:17:49.725 [springListenerContainerRABC-1] INFO RabbitMQListener - Message :: test1

00:17:49.725 [springListenerContainerRABC-1] INFO RabbitMQListener - Received message for consumer: XYZConsumer

00:17:49.725 [springListenerContainerRABC-1] INFO RabbitMQListener - Message :: test2

00:17:49.725 [springListenerContainerRABC-1] INFO RabbitMQListener - Received message for consumer: XYZConsumer

00:17:49.725 [springListenerContainerRABC-1] INFO RabbitMQListener - Message :: test3

00:17:49.725 [springListenerContainerRABC-1] INFO RabbitMQListener - Received message for consumer: XYZConsumer

00:17:49.725 [springListenerContainerRABC-1] INFO RabbitMQListener - Message :: test4

[org.springframework.amqp.rabbit.RabbitListenerEndpointContainer#0-1] INFO RabbitMQListener - **Received message for consumer: null**

[org.springframework.amqp.rabbit.RabbitListenerEndpointContainer#0-1] INFO RabbitMQListener - Message :: test5

@EnableRabbit
@Service 
public class RabbitMQListener implements MessageListener {
    @Autowired
    private ApplicationContext applicationContext;

    protected static Logger logger = LoggerFactory.getLogger(RabbitMQListener.class);

    private TaskExecutor taskExecutor;
    private RabbitSender responseSender;
    private String consumerType;
    private String encoding;

     public TaskExecutor getTaskExecutor() {
        return taskExecutor;
    }

    public void setTaskExecutor(TaskExecutor taskExecutor) {
        this.taskExecutor = taskExecutor;
    }

    public void setResponseSender(RabbitSender responseSender) {
        this.responseSender = responseSender;
    }

    public void setConsumerType(String consumerType) {
        this.consumerType = consumerType;
    }

    public void setEncoding(String encoding) {
        this.encoding = encoding;
    }

    @Override
    @RabbitListener(containerFactory = Constants.CONTAINER_FACTORY, queues = "#{'${QM_QUEUES}'.split(',')}")
    public void onMessage(final Message arg0) {

        if (arg0 != null) {
            try {
                String message = new String(arg0.getBody());
                logger.info("Message Properties class: " + arg0.getClass());
                logger.info("Message Properties: " + arg0.getMessageProperties());
                logger.info("Received message for consumer: " + this.consumerType);
                logger.info("Message :: " + message);
                Object bean = applicationContext.getBean(this.consumerType);
                if (bean instanceof Consumer) {
                    logger.debug("Processing message for consumer: " + this.consumerType);
                    Consumer consumer = (Consumer)bean;
                    consumer.setMessage(message);
                    consumer.setResponseSender(responseSender);
                    logger.debug("Executing consumer: " + this.consumerType);
                    taskExecutor.execute(consumer);
                } else {
                    logger.info("Could not process message due to invalid consumer.");
                }

            } 
            catch (AmqpException e1) {
                logger.error("Spring AMQP error processing message.", e1.getMessage());
            }
            catch (Exception e2) {
                logger.error("General error processing message.", e2.getMessage());
            }
        }
        else {
            logger.debug("message received is NULL");
        }

    }


}