spring-boot - Spring-Kafka 中的 poll() 和 commitAsync()

Question

我正在尝试用 java 编写一个 kafka 消费者应用程序Springboot 平台。早些时候，我用纯 Java 编写了代码，但是现在转换为 spring-kafka，因为它可以提供一些优势普通的java。我确实有几个问题想弄明白。

• 看来我不必在 spring-kafka 中显式地进行 poll() 循环它会由@KafkaListener 自动处理吗？

• 我已经设置了 enable.auto.commit='false'，因为我必须做一些事情在提交偏移量之前进行处理，我怎样才能在中执行 commitAsync()Spring-Kafka？

  消费者配置.java :

  @EnableKafka
  @Configuration
  public class KafkaConsumerConfig {
  
      @Value("${app.kafka_brokers}")
      private String KAFKA_BROKERS;
  
      @Value("${app.topic}")
      private String KAFKA_TOPIC;
  
      @Value("${app.group_id_config}")
      private String GROUP_ID_CONFIG;
  
      @Value("${app.schema_registry_url}")
      private String SCHEMA_REGISTRY_URL;
  
      @Value("${app.offset_reset}")
      private String OFFSET_RESET;
  
      @Value("${app.max_poll_records}")
      private String MAX_POLL_RECORDS;
  
      @Value("${app.security.protocol}")
      private String SSL_PROTOCOL;
  
      @Value("${app.ssl.truststore.password}")
      private String SSL_TRUSTSTORE_SECURE;
  
      @Value("${app.ssl.keystore.password}")
      private String SSL_KEYSTORE_SECURE;
  
      @Value("${app.ssl.key.password}")
      private String SSL_KEY_SECURE;
  
      @Value("${app.ssl.truststore.location}")
      private String SSL_TRUSTSTORE_LOCATION_FILE_NAME;
  
      @Value("${app.ssl.keystore.location}")
      private String SSL_KEYSTORE_LOCATION_FILE_NAME;
  
      @Bean
      public ConsumerFactory<String, String> consumerFactory(){
  
          Map<String, Object> props = new HashMap<>();
          props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG,KAFKA_BROKERS);
          props.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, OFFSET_RESET);
          props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());
          props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, KafkaAvroDeserializer.class.getName());
          props.put(ConsumerConfig.GROUP_ID_CONFIG, GROUP_ID_CONFIG);
          props.put(KafkaAvroDeserializerConfig.SCHEMA_REGISTRY_URL_CONFIG, SCHEMA_REGISTRY_URL);
          props.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, "false");
  
          props.put(CommonClientConfigs.SECURITY_PROTOCOL_CONFIG, SSL_PROTOCOL);
          props.put(SslConfigs.SSL_TRUSTSTORE_LOCATION_CONFIG,SSL_TRUSTSTORE_LOCATION_FILE_NAME);
          props.put(SslConfigs.SSL_TRUSTSTORE_PASSWORD_CONFIG, SSL_TRUSTSTORE_SECURE);
          props.put(SslConfigs.SSL_KEYSTORE_LOCATION_CONFIG,SSL_KEYSTORE_LOCATION_FILE_NAME);
          props.put(SslConfigs.SSL_KEYSTORE_PASSWORD_CONFIG, SSL_KEYSTORE_SECURE);
          props.put(SslConfigs.SSL_KEY_PASSWORD_CONFIG, SSL_KEY_SECURE);
  
          return new DefaultKafkaConsumerFactory<>(props);
  
      }
  
      @Bean
      ConcurrentKafkaListenerContainerFactory<String, String> 
      kafkaListenerContainerFactory() {
  
        ConcurrentKafkaListenerContainerFactory<String, String> factory =
                              new ConcurrentKafkaListenerContainerFactory<>();
        factory.setConsumerFactory(consumerFactory());
        factory.setConcurrency(3);
        return factory;
    }
  
  }
  

KafkaConsumer.java :

@Component
public class KafkaConsumer {
    
    @KafkaListener(topics = "topic", groupId = "group")
    public void run(ConsumerRecord<String, GenericRecord> record) {
        
        System.out.println(record);
        
    <-- how to asyncCommit()--> 
    }

}

Answer 1

首先，我建议您使用 Spring kafka 设置的属性和自动配置，而不是自己创建，因为它遵循DRY 原则:不要重复自己。

spring:
  kafka:
    bootstrap-servers: ${app.kafka_brokers}
    consumer:
      auto-offset-reset: ${app.offset_reset}
      enable-auto-commit: false   // <---- disable auto committing
    ssl:
      protocol: ${app.security.protocol}
      key-store-location: ${app.ssl.keystore.location}
      key-store-password:  ${app.ssl.keystore.password}
      trust-store-location: ${app.ssl.truststore.location}
      trust-store-password: ${app.ssl.truststore.password}
  // And other properties
    listener:
      ack-mode: manual // This is what you need

AckMode 文档:https://docs.spring.io/spring-kafka/api/org/springframework/kafka/listener/ContainerProperties.AckMode.html

本质上，manual是异步确认，而manual_immediate是同步的。

然后在您的 @KafkaListener 组件中，您可以注入(inject) org.springframework.kafka.support.Acknowledgment 对象确认您的消息。

@Component
public class KafkaConsumer {
    
    @KafkaListener(topics = "topic", groupId = "group")
    public void run(ConsumerRecord<String, GenericRecord> record, Acknowledgment acknowledgment) {
        
        System.out.println(record);
        
        acknowledgment.acknowledge();
    }

}

这是关于可以注入(inject)到@KafkaListener 方法中的内容的文档:https://docs.spring.io/spring-kafka/reference/html/#message-listeners