Rabbitmq中的键与队列名称（以及@RabbitListener中为什么两者都存在的原因）

Question

我正在阅读这篇文章，它说在fanout以外的消息交换中，消息被路由到与其键匹配的队列中。

如果是这样，那么为什么在以下注释中有两个参数（ @Queue value和key ）？ 仅指定队列名称还不够吗？

@RabbitListener(bindings = @QueueBinding(value = @Queue(value = RabbitMQConfiguration.AUTHENTICATION_EMAILS_QUEUE, durable = "true"), exchange = @Exchange(value = RabbitMQConfiguration.EMAIL_MESSAGE_EXCHANGE_NAME), key = "accountActivationEmail"))
public void receiveMessage(Map<String, String> message) {
    this.sendEmail(getEmail(message));
}

另一个问题：有了您为侦听器看到的注释，我是否需要有一个单独的@Configuration类来指定MessageListenerAdapter ， SimpleMessageListenerContainer ， Binding ， Exchange和Queue ，如下所示：

@Configuration
public class RabbitMQConfiguration {

    public final static String AUTHENTICATION_EMAILS_QUEUE = "AUTHENTICATION_EMAILS_QUEUE";
    public final static String EMAIL_MESSAGE_EXCHANGE_NAME = "EMAIL_EVENTS";

    @Bean
    public Queue authenticationEmailsQueue() {
        return new Queue(AUTHENTICATION_EMAILS_QUEUE, false);
    }

    @Bean
    public DirectExchange emailMessagesExchange() {
        return new DirectExchange(EMAIL_MESSAGE_EXCHANGE_NAME);
    }

    @Bean
    public Binding authenticationEmailMQBinding(Queue queue, DirectExchange exchange) {
        return BindingBuilder.bind(queue).to(exchange).with(AUTHENTICATION_EMAILS_QUEUE);
    }

    @Bean
    public SimpleMessageListenerContainer authenticationEmailContainer(ConnectionFactory connectionFactory,
    MessageListenerAdapter listenerAdapter) {
        SimpleMessageListenerContainer container = new SimpleMessageListenerContainer();
        container.setConnectionFactory(connectionFactory);
        container.setQueueNames(AUTHENTICATION_EMAILS_QUEUE);
        container.setMessageListener(listenerAdapter);
        return container;
    }

    @Bean
    public MessageListenerAdapter authenticationEmailHandlerAdapter(AuthenticationEmailHandler receiver) {
        return new MessageListenerAdapter(receiver, "receiveMessage");
    }

}