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1、简介

        对于经常需要变更kafka主题的场景，为了实现动态监听topic的功能，可以使用以下方式。

2、使用步骤

2.1、添加依赖

<dependency><groupId>org.springframework.kafka</groupId><artifactId>spring-kafka</artifactId><version>2.8.1</version>
</dependency>

2.2、nacos中配置

    # kafka 配置
spring:kafka:bootstrap-servers: ip地址:9092topics: topic1,tpic2producer:key-serializer: org.apache.kafka.common.serialization.StringSerializervalue-serializer: org.apache.kafka.common.serialization.StringSerializerenable-idempotence: trueacks: alltransactional-id: kafka-groupconsumer:key-deserializer: org.apache.kafka.common.serialization.StringDeserializervalue-deserializer: org.apache.kafka.common.serialization.StringDeserializergroup-id: kafka-clickhouse-groupauto-offset-reset: latestenable-auto-commit: falseisolation-level: read_committedallow-auto-create-topics: truelistener:ack-mode: MANUAL_IMMEDIATEconcurrency: 3

2.3、配置类

package org.aecsi.kafkadatatock.config;import lombok.RequiredArgsConstructor;
import org.apache.kafka.clients.admin.AdminClient;
import org.apache.kafka.clients.admin.ListTopicsResult;
import org.apache.kafka.clients.consumer.ConsumerConfig;
import org.apache.kafka.clients.producer.ProducerConfig;
import org.apache.kafka.common.serialization.StringDeserializer;
import org.apache.kafka.common.serialization.StringSerializer;
import org.springframework.boot.ApplicationRunner;
import org.springframework.boot.autoconfigure.kafka.KafkaProperties;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.kafka.annotation.EnableKafka;
import org.springframework.kafka.config.ConcurrentKafkaListenerContainerFactory;
import org.springframework.kafka.config.KafkaListenerEndpointRegistry;
import org.springframework.kafka.core.*;
import org.springframework.kafka.listener.ContainerProperties;
import org.springframework.kafka.transaction.KafkaTransactionManager;import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ExecutionException;@Configuration
@RequiredArgsConstructor
@EnableKafka
@RefreshScope
public class KafkaConfig {private final KafkaProperties kafkaProperties;@Beanpublic KafkaAdmin kafkaAdmin() {return new KafkaAdmin(kafkaProperties.buildAdminProperties());}@Beanpublic AdminClient adminClient(KafkaAdmin kafkaAdmin) {return AdminClient.create(kafkaAdmin.getConfigurationProperties());}@Beanpublic ProducerFactory<String, String> producerFactory() {Map<String, Object> configProps = new HashMap<>(kafkaProperties.buildProducerProperties());configProps.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);configProps.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class);configProps.put(ProducerConfig.ENABLE_IDEMPOTENCE_CONFIG, true);configProps.put(ProducerConfig.ACKS_CONFIG, "all");configProps.put(ProducerConfig.TRANSACTIONAL_ID_CONFIG, "kafka-clickhouse-producer");DefaultKafkaProducerFactory<String, String> factory = new DefaultKafkaProducerFactory<>(configProps);factory.setTransactionIdPrefix("kafka-clickhouse-producer-");return factory;}@Beanpublic KafkaTemplate<String, String> kafkaTemplate(ProducerFactory<String, String> producerFactory) {return new KafkaTemplate<>(producerFactory);}@Bean@RefreshScopepublic ConsumerFactory<String, String> consumerFactory() {Map<String, Object> configProps = new HashMap<>(kafkaProperties.buildConsumerProperties());configProps.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);configProps.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);configProps.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, false);configProps.put(ConsumerConfig.ALLOW_AUTO_CREATE_TOPICS_CONFIG, true);configProps.put(ConsumerConfig.ISOLATION_LEVEL_CONFIG, "read_committed");return new DefaultKafkaConsumerFactory<>(configProps);}@Beanpublic KafkaTransactionManager<String, String> transactionManager(ProducerFactory<String, String> producerFactory) {return new KafkaTransactionManager<>(producerFactory);}@Beanpublic ConcurrentKafkaListenerContainerFactory<String, String> kafkaListenerContainerFactory(ConsumerFactory<String, String> consumerFactory,KafkaTransactionManager<String, String> transactionManager) {ConcurrentKafkaListenerContainerFactory<String, String> factory = new ConcurrentKafkaListenerContainerFactory<>();factory.setConsumerFactory(consumerFactory);factory.getContainerProperties().setAckMode(ContainerProperties.AckMode.MANUAL_IMMEDIATE);factory.getContainerProperties().setTransactionManager(transactionManager);return factory;}@Bean@RefreshScopepublic ConcurrentKafkaListenerContainerFactory<String, String> kafkaListenerContainerFactory() {ConcurrentKafkaListenerContainerFactory<String, String> factory = new ConcurrentKafkaListenerContainerFactory<>();factory.setConsumerFactory(consumerFactory());factory.setAutoStartup(true);return factory;}@Beanpublic ApplicationRunner kafkaListenerStarter(KafkaListenerEndpointRegistry registry) {return args -> {// 启动所有 Kafka 监听器registry.start();};}
}

接收消息类

@KafkaListener(topics = "#{'${spring.kafka.topics}'.split(',')}", autoStartup = "false")@Transactional(transactionManager = "transactionManager")public void processMessage(ConsumerRecord<String, String> record,Acknowledgment acknowledgment,@Header(KafkaHeaders.RECEIVED_TOPIC) String topic,@Header(KafkaHeaders.RECEIVED_TIMESTAMP) long timestamp) {try {log.info("kafka 接受 topic: {} 消息", topic);
//          处理消息acknowledgment.acknowledge();} catch (Exception e) {log.error("Error processing message for topic {}: {}", topic, e.getMessage());throw e;}}

 主启动类添加一个注解

@EnableConfigurationProperties(KafkaProperties.class)

3、总结

      实现kafka动态获取topic还有其他方式，博主目前只验证这一种，其他方式待更新。