使用Spring Kafka添加自定义标题

Spring Kafka提供了headers支持 版本2.0 : https://docs.spring.io/spring-kafka/docs/2.1.2.RELEASE/reference/html/_reference.html#headers

你可以拥有它 KafkaHeaderMapper 实例,并使用它填充 Message 在通过发送之前 KafkaTemplate.send(Message<?> message) . 或者你可以用平原 KafkaTemplate.send(ProducerRecord<K, V> record) .

当您使用接收记录时 KafkaMessageListenerContainer 这个 卡夫卡·海德堡 可通过 MessagingMessageConverter 注入到 RecordMessagingMessageListenerAdapter .

因此,任何自定义标头都可以通过任何一种方式进行传输。

当我偶然发现这个问题时,我正在寻找答案。但是我使用 ProducerRecord<?, ?> 类而不是 Message<?> ,因此标题映射器似乎不相关。

下面是我添加自定义标题的方法:

var record = new ProducerRecord<String, String>(topicName, "Hello World");
record.headers().add("foo", "bar".getBytes());
kafkaTemplate.send(record);

现在,为了阅读标题(在使用之前),我添加了一个自定义拦截器。

import java.util.List;
import lombok.extern.slf4j.Slf4j;
import org.apache.kafka.clients.consumer.ConsumerInterceptor;
import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.apache.kafka.clients.consumer.ConsumerRecords;

@Slf4j
public class MyConsumerInterceptor implements ConsumerInterceptor<Object, Object> {

    @Override
    public ConsumerRecords<Object, Object> onConsume(ConsumerRecords<Object, Object> records) {
        Set<TopicPartition> partitions = records.partitions();
        partitions.forEach(partition -> interceptRecordsFromPartition(records.records(partition)));

        return records;
    }

    private void interceptRecordsFromPartition(List<ConsumerRecord<Object, Object>> records) {
        records.forEach(record -> {
            var myHeaders = new ArrayList<Header>();
            record.headers().headers("MyHeader").forEach(myHeaders::add);
            log.info("My Headers: {}", myHeaders);
            // Do with header as you see fit
        });
    }

    @Override public void onCommit(Map<TopicPartition, OffsetAndMetadata> offsets) {}
    @Override public void close() {}
    @Override public void configure(Map<String, ?> configs) {}
}

最后一位是使用以下(Spring Boot)配置向Kafka使用者容器注册此拦截器:

import java.util.Map;
import org.apache.kafka.clients.consumer.ConsumerConfig;
import org.springframework.boot.autoconfigure.kafka.KafkaProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.kafka.core.ConsumerFactory;
import org.springframework.kafka.core.DefaultKafkaConsumerFactory;

@Configuration
public class MessagingConfiguration {

    @Bean
    public ConsumerFactory<?, ?> kafkaConsumerFactory(KafkaProperties properties) {
        Map<String, Object> consumerProperties = properties.buildConsumerProperties();
        consumerProperties.put(ConsumerConfig.INTERCEPTOR_CLASSES_CONFIG, MyConsumerInterceptor.class.getName());
        return new DefaultKafkaConsumerFactory<>(consumerProperties);
    }

}