创建没有注释和 Spring Boot 的 KafkaListener

Question

我正在尝试在不使用 @KafkaListener 注释的情况下为主题创建 Kafka Consumer。我想这样做是因为我试图在不使用 spring boot 的情况下根据 application.properties 动态创建侦听器。

我认为最好的方法是手动创建一个 KafkaListenerContainerFactory 有人可以提供一个如何在它自己的类中执行此操作的示例。

Answer 1

• 与春天

@Bean
public KafkaMessageListenerContainer<String, String> messageListenerContainer(String topic) {

    ContainerProperties containerProperties = new ContainerProperties(topic);
    containerProperties.setMessageListener(new MyMessageListener());

    ConsumerFactory<String, String> consumerFactory = new DefaultKafkaConsumerFactory<>(consumerProperties());
    KafkaMessageListenerContainer<String, String> listenerContainer = new KafkaMessageListenerContainer<>(consumerFactory, containerProperties);
    listenerContainer.setAutoStartup(false);
    // bean name is the prefix of kafka consumer thread name
    listenerContainer.setBeanName("kafka-message-listener");
    return listenerContainer;
}

private Map<String, Object> consumerProperties(){
    Map<String, Object> props = new HashMap<>();
    props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
    props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
    props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
    props.put(ConsumerConfig.GROUP_ID_CONFIG, "test");
    return props;
}

static class MyMessageListener implements MessageListener<String, String> 
    @Override
    public void onMessage(ConsumerRecord<String, String> data) {
        // do something
    }
}

• 没有 spring
  kafka 文档是非常有帮助的。下面是它的一个使用示例。

     Properties props = new Properties();
     props.setProperty("bootstrap.servers", "localhost:9092");
     props.setProperty("group.id", "test");
     props.setProperty("enable.auto.commit", "true");
     props.setProperty("auto.commit.interval.ms", "1000");
     props.setProperty("key.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
     props.setProperty("value.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
     KafkaConsumer<String, String> consumer = new KafkaConsumer<>(props);
     consumer.subscribe(Arrays.asList("foo", "bar"));
     while (true) {
         ConsumerRecords<String, String> records = consumer.poll(Duration.ofMillis(100));
         for (ConsumerRecord<String, String> record : records)
             System.out.printf("offset = %d, key = %s, value = %s%n", record.offset(), record.key(), record.value());
     }