[英]poll() and commitAsync() in Spring-Kafka
我正在尝试在 java 中在 Springboot 平台上编写一个 kafka 消费者应用程序。 早些时候,我用普通 java 编写了代码,但现在转换为 spring-kafka,因为它比普通 java 有一些优势。我确实有几个问题想了解。
似乎我不必在 spring-kafka 中显式 poll() 循环,它会由@KafkaListener 自动处理吗?
我已经设置了enable.auto.commit='false',因为我必须在提交偏移量之前做一些处理,我如何在Spring-Kafka中执行commitAsync()?
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; } }
卡夫卡消费者.java:
@Component
public class KafkaConsumer {
@KafkaListener(topics = "topic", groupId = "group")
public void run(ConsumerRecord<String, GenericRecord> record) {
System.out.println(record);
<-- how to asyncCommit()-->
}
}
首先,我建议您使用 Spring kafka 设置的属性和自动配置,而不是创建自己的,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
本质上, manual
是一种异步确认,而manual_immediate
是同步的。
然后在您的@KafkaListener
组件中,您可以注入org.springframework.kafka.support.Acknowledgment
object 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();
}
}
这是可以注入@KafkaListener
方法的文档: https://docs.spring.io/spring-kafka/reference/html/#message-listeners
监听器容器会在监听器正常退出时提交偏移量,具体取决于容器的AckMode
属性; AckMode.BATCH
(默认)表示轮询返回的所有记录的偏移量将在所有处理完成后提交, AckMode.RECORD
表示每个偏移量将在侦听器退出时立即提交。
sync
比。 async
由syncCommits
容器属性控制。
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