java - QueueMessageHandler 的用途是什么

Question

下面粘贴的代码中的 QueueMessageHandler 的用途是什么？在下面的示例中，queueMessageHandler 似乎没有执行太多操作。

@Bean
public SimpleMessageListenerContainer simpleMessageListenerContainer(AmazonSQSAsync amazonSQSAsync) {
    SimpleMessageListenerContainer simpleMessageListenerContainer = new SimpleMessageListenerContainer();
    simpleMessageListenerContainer.setAmazonSqs(amazonSQSAsync);
    simpleMessageListenerContainer.setMessageHandler(queueMessageHandler());
    simpleMessageListenerContainer.setMaxNumberOfMessages(10);
    simpleMessageListenerContainer.setTaskExecutor(threadPoolTaskExecutor());
    return simpleMessageListenerContainer;
}


@Bean
public QueueMessageHandler queueMessageHandler() {
    QueueMessageHandlerFactory queueMessageHandlerFactory = new QueueMessageHandlerFactory();
    queueMessageHandlerFactory.setAmazonSqs(amazonSQSAsync());
    QueueMessageHandler queueMessageHandler = queueMessageHandlerFactory.createQueueMessageHandler();
    return queueMessageHandler;
}

Answer 1

QueueMessageHandler 扩展 AbstractMethodMessageHandler :

Abstract base class for HandlerMethod-based message handling. Provides most of the logic required to discover handler methods at startup, find a matching handler method at runtime for a given message and invoke it.

Also supports discovering and invoking exception handling methods to process exceptions raised during message handling.