如何使用工厂为特定主题配置Spring Kafka Listener？

Question

我希望能够通过属性阅读主题，而无需在 Kafka 侦听器注释上指定任何内容。不使用Spring靴。

我尝试通过“topics”键直接从properties对象中读取主题。这将产生一个错误:< code>IllegalStateException:必须提供topics、topicPattern或topicPartitions。

// some class
@KafkaListener
public void listener(List<String> messages) {
  System.out.print(messages);
}

//some other class
@Bean
public ConsumerFactory<String, String> consumerFactory(Properties topicProp) {
  return new DefaultKafkaConsumerFactory(topicProp);
}

@Bean
public ConcurrentKafkaListenerContainerFactory<String, String> kafkaListenerContainerFactory() {
  ConcurrentKafkaListenerContainerFactory<String, String> factory = new ConcurrentKafkaListenerContainerFactory<>();

  Properties prop = new Properties();
  prop.setProperty("topics", "my-custom-topic");

  factory.setConsumerFactory(this.consumerFactory(prop));
  return factory;
}

Is this possible?

Answer 1

您可以在主题中引用其他 bean（或有关 bean 的方法）

java prettyprint-override">@Bean
public String topicName() {
    return "my-custom-topic";
}

...

@KafkaListener(topics = "#{@topicName}")
...

或者

@KafkaListener(topics = "#{@someBean.someMethod()}")