Kafka消费者无法稳定解析监听方法

该问题可能出现在Spring Boot应用程序中，原因是在并发处理消息时，Kafka消费者未能正确解析监听方法。为解决此问题，可以使用@KafkaListener注解的containerFactory属性来设置KafkaListenerContainerFactory，并将KafkaListenerContainerFactory的concurrency属性设置为大于1的值。以下是示例代码：

@Configuration @EnableKafka public class KafkaConsumerConfig {

@Bean
public KafkaListenerContainerFactory<ConcurrentMessageListenerContainer<String, String>>
kafkaListenerContainerFactory() {
    ConcurrentKafkaListenerContainerFactory<String, String> factory =
            new ConcurrentKafkaListenerContainerFactory<>();
    factory.setConcurrency(3); // 设置并发数为3
    factory.setConsumerFactory(consumerFactory());
    factory.setAutoStartup(true);
    factory.getContainerProperties().setPollTimeout(3000);
    return factory;
}

@Bean
public ConsumerFactory<String, String> consumerFactory() {
    Map<String, Object> props = new HashMap<>();
    props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
    props.put(ConsumerConfig.GROUP_ID_CONFIG, "group_id");
    props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
    props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
    return new DefaultKafkaConsumerFactory<>(props);
}

}

@Service public class KafkaConsumer {

@KafkaListener(topics = "myTopic", groupId = "group_id", containerFactory = "kafkaListenerContainerFactory")
public void consume(String message) {
    // 处理接收到的消息
}

}

在上面的示例中，KafkaListenerContainerFactory的并发属性设置为3，因此每个Kafka消费者将通过最多3个线程并发地处理接收到的消息。