自定义kafka客户端消费topic

结论

使用自定义的KafkaConsumer给spring进行管理，之后在注入topic的set方法中，开单线程主动订阅和读取该topic的消息。

1 背景

后端服务不需要启动时就开始监听消费，而是根据启动的模块或者用户自定义监听需要监听或者停止的topic

2 spring集成2.1.8.RELEASE版本不支持autoStartup属性

使用的spring集成2.1.8.RELEASE的版本，在@KafkaListener注解中没有找到可以直接配置属性autoStartup = "false"来手动启动topic，可能是版本低的原因，如果有可以支持的版本，也可以打在评论区，我去验证一下。

<dependency><groupId>org.springframework.kafka</groupId><artifactId>spring-kafka</artifactId><version>2.1.8.RELEASE</version>
</dependency>

@KafkaListener(topics = "<Kafka主题>", autoStartup = "false") 
public void receive(String message) {    // 处理接收到的消息 
}

3 自定义kafka客户端消费topic

3.1 yml配置

spring:kafka:bootstrap-servers: 19.125.105.6:9092,19.125.105.7,19.125.105.8:9092consumer:group-id: data-devenable-auto-commit: trueauto-offset-reset: latestauto-commit-interval: 1000topic:costomTopic: costomData

3.2 KafkaConfig客户端配置

kafka其他配置项和原有的kafka客户端配置一样，只有额外增加了一个cutomConsumer让spring来管理，方便手动启动客户端来使用

import org.apache.kafka.clients.consumer.ConsumerConfig;
import org.apache.kafka.clients.consumer.KafkaConsumer;
import org.apache.kafka.clients.producer.ProducerConfig;
import org.apache.kafka.common.serialization.StringDeserializer;
import org.apache.kafka.common.serialization.StringSerializer;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.kafka.config.ConcurrentKafkaListenerContainerFactory;
import org.springframework.kafka.config.KafkaListenerContainerFactory;
import org.springframework.kafka.core.*;
import org.springframework.kafka.listener.ConcurrentMessageListenerContainer;import java.util.HashMap;
import java.util.Map;@Configuration
public class KafkaConfig {@Value("${spring.kafka.bootstrap-servers}")private String bootstrapServers;@Value("${spring.kafka.consumer.group-id}")private String groupId;@Value("${spring.kafka.consumer.enable-auto-commit}")private boolean enableAutoCommit;@Value("${spring.kafka.consumer.auto-offset-reset}")private String autoOffsetReset;//    @Value("${spring.kafka.listener.concurrency}")
//    private Integer concurrency;@Value("${spring.kafka.consumer.auto-commit-interval}")private Integer autoCommitInterval;@Beanpublic KafkaTemplate<String, String> kafkaTemplate() {return new KafkaTemplate<>(producerFactory());}@BeanKafkaListenerContainerFactory<ConcurrentMessageListenerContainer<Integer, String>> kafkaContainerFactory() {ConcurrentKafkaListenerContainerFactory<Integer, String> factory = new ConcurrentKafkaListenerContainerFactory<>();factory.setConsumerFactory(consumerFactory());// concurrencyfactory.setConcurrency(3);factory.getContainerProperties().setPollTimeout(3000);return factory;}private ProducerFactory<String, String> producerFactory() {return new DefaultKafkaProducerFactory<>(producerConfigs());}public ConsumerFactory<Integer, String> consumerFactory() {return new DefaultKafkaConsumerFactory<>(consumerConfigs());}private Map<String, Object> producerConfigs() {Map<String, Object> props = new HashMap<>();props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);props.put(ProducerConfig.RETRIES_CONFIG, 0);props.put(ProducerConfig.ACKS_CONFIG, "1");props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class);return props;}private Map<String, Object> consumerConfigs() {Map<String, Object> props = new HashMap<>();props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);props.put(ConsumerConfig.GROUP_ID_CONFIG, groupId);props.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, enableAutoCommit);props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);props.put(ConsumerConfig.AUTO_COMMIT_INTERVAL_MS_CONFIG, autoCommitInterval);props.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, autoOffsetReset);return props;}@Beanpublic KafkaConsumer cutomConsumer() {// 新建一个自定义启动消费者KafkaConsumer consumer = new KafkaConsumer<>(consumerConfigs());return consumer;}
}

3.3 手动启动消费客户端

这里手动启动消费客户端只有在配置了costomTopic才开始启动，如果需要动态指定启停topic

@Component
public class CutomKafkaConsumer {// 使用cutomConsumer实例消费@Autowiredprivate KafkaConsumer cutomConsumer;@Value("${spring.kafka.topic.costomTopic:}")public void setCostomTopic(String costomTopic) {// 手动启动消费类,防止下级模块默认不配置costomTopic导致启动报错if (StringUtils.isEmpty(costomTopic)) {return;}// 使这个消费者订阅对应话题cutomConsumer.subscribe(Collections.singleton(costomTopic));// 单线程拉取消息ExecutorService consumerExecutor = Executors.newSingleThreadExecutor();consumerExecutor.submit(new Runnable() {@Overridepublic void run() {while (true) {ConsumerRecords<String, String> records = cutomConsumer.poll(3000);if (!records.iterator().hasNext()) {continue;}try {// 捕获异常,防止顶级消费循环被异常中断records.forEach(record -> operate(record));} catch (Exception e) {log.error("消费数据失败,失败原因: {}", e.getMessage(), e);}// 通过异步的方式提交位移cutomConsumer.commitAsync(((offsets, exception) -> {if (exception == null) {offsets.forEach((topicPartition, metadata) -> {System.out.println(topicPartition + " -> offset=" + metadata.offset());});} else {exception.printStackTrace();// 如果出错了，同步提交位移cutomConsumer.commitSync(offsets);}}));}}});}
}    public void operate(ConsumerRecord<String, String> record) {log.info("kafkaTwoContainerFactory.operate start. key: {}, value : {}", record.key(), record.value());
}

参考：
Kafka消费者——API开发
Kafka Consumer如何实现精确一次消费数据
Apache Kafka - 灵活控制Kafka消费_动态开启/关闭监听实现
@KafkaListener 详解及消息消费启停控制
kafka多个消费者消费一个topic_kafka消费者组与重平衡机制，了解一下
kafka学习（五）：消费者分区策略（再平衡机制）
Kafka 3.0 源码笔记(3)-Kafka 消费者的核心流程源码分析