1 自動配置

自動配置實現在 org.springframework.boot.autoconfigure.kafka.KafkaAutoConfiguration

配置類為:

@ConfigurationProperties(prefix = "spring.kafka")
public class KafkaProperties {

......

}

所以使用spring boot 預設的自動配置，kafka的配置都已spring.kafka開頭，如：

#kafka預設消費者配置
spring.kafka.consumer.bootstrap-servers=192.168.0.15:9092
spring.kafka.consumer.enable-auto-commit=false
spring.kafka.consumer.auto-offset-reset=earliest
#kafka預設生產者配置
spring.kafka.producer.bootstrap-servers=192.168.0.15:9092
spring.kafka.producer.acks=-1
spring.kafka.client-id=kafka-producer
spring.kafka.producer.batch-size=5

 

2 自定義配置

配置類org.springframework.boot.autoconfigure.kafka.KafkaProperties中並沒有涵蓋所有的org.apache.kafka.clients.producer.ProducerConfig和org.apache.kafka.clients.consumer.ConsumerConfig中的配置，這就導致某些特殊配置不能依賴spring boot自動建立，需要我們手動建立Poducer和comsumer。

生產端自定義配置例子:

package cn.ztuo.bitrade.config;

import java.util.HashMap;
import java.util.Map;

import org.apache.kafka.clients.producer.ProducerConfig;
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.annotation.EnableKafka;
import org.springframework.kafka.core.DefaultKafkaProducerFactory;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.kafka.core.ProducerFactory;

@Configuration
@EnableKafka
public class KafkaProducerConfiguration {

	@Value("${spring.kafka.bootstrap-servers}")
	private String servers;
	@Value("${spring.kafka.producer.retries}")
	private int retries;
	@Value("${spring.kafka.producer.batch.size}")
	private int batchSize;
	@Value("${spring.kafka.producer.linger}")
	private int linger;
	@Value("${spring.kafka.producer.buffer.memory}")
	private int bufferMemory;
	// 建立生產者配置map，ProducerConfig中的可配置屬性比spring boot自動配置要多
	public Map<String, Object> producerConfigs() {
		Map<String, Object> props = new HashMap<>();
		props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, servers);
		props.put(ProducerConfig.RETRIES_CONFIG, retries);
		props.put(ProducerConfig.BATCH_SIZE_CONFIG, batchSize);
		props.put(ProducerConfig.LINGER_MS_CONFIG, linger);
		props.put(ProducerConfig.BUFFER_MEMORY_CONFIG, bufferMemory);
//		props.put(ProducerConfig.PARTITIONER_CLASS_CONFIG, "cn.ztuo.bitrade.kafka.kafkaPartitioner");
		props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
		props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
		return props;
	}

	/**
	 * 不使用spring boot的KafkaAutoConfiguration預設方式建立的DefaultKafkaProducerFactory，重新定義
	 * @return
	 */
	public ProducerFactory<String, String> producerFactory() {
		return new DefaultKafkaProducerFactory<>(producerConfigs());
	}
	/**
	 * 不使用spring boot的KafkaAutoConfiguration預設方式建立的KafkaTemplate，重新定義
	 * @return
	 */
	@Bean
	public KafkaTemplate<String, String> kafkaTemplate() {
		return new KafkaTemplate<String, String>(producerFactory());
	}

}

消費端自定義配置例子：

package cn.ztuo.bitrade.config;

import java.util.HashMap;
import java.util.Map;

import org.apache.kafka.clients.consumer.ConsumerConfig;
import org.apache.kafka.common.serialization.StringDeserializer;
import org.springframework.beans.factory.annotation.Value;
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.KafkaListenerContainerFactory;
import org.springframework.kafka.core.ConsumerFactory;
import org.springframework.kafka.core.DefaultKafkaConsumerFactory;
import org.springframework.kafka.listener.ConcurrentMessageListenerContainer;
//這裡建立了對應型別的bean之後，org.springframework.boot.autoconfigure.kafka.KafkaAutoConfiguration中的對應Bean定義將不起作用。
@Configuration
@EnableKafka
public class KafkaConsumerConfiguration {

	@Value("${spring.kafka.bootstrap-servers}")
	private String servers;
	@Value("${spring.kafka.consumer.enable.auto.commit}")
	private boolean enableAutoCommit;
	@Value("${spring.kafka.consumer.session.timeout}")
	private String sessionTimeout;
	@Value("${spring.kafka.consumer.auto.commit.interval}")
	private String autoCommitInterval;
	@Value("${spring.kafka.consumer.group.id}")
	private String groupId;
	@Value("${spring.kafka.consumer.auto.offset.reset}")
	private String autoOffsetReset;
	@Value("${spring.kafka.consumer.concurrency}")
	private int concurrency;
	@Value("${spring.kafka.consumer.maxPollRecordsConfig}")
	private int maxPollRecordsConfig;
	//構造消費者屬性map，ConsumerConfig中的可配置屬性比spring boot自動配置要多
	public Map<String, Object> consumerConfigs() {
		Map<String, Object> propsMap = new HashMap<>();
		propsMap.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, servers);
		propsMap.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, enableAutoCommit);
		propsMap.put(ConsumerConfig.AUTO_COMMIT_INTERVAL_MS_CONFIG, autoCommitInterval);
		propsMap.put(ConsumerConfig.SESSION_TIMEOUT_MS_CONFIG, sessionTimeout);
		propsMap.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());
		propsMap.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class.getName());
		propsMap.put(ConsumerConfig.GROUP_ID_CONFIG, groupId);
		propsMap.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, autoOffsetReset);
		propsMap.put(ConsumerConfig.MAX_POLL_RECORDS_CONFIG, maxPollRecordsConfig);// 每個批次獲取數
		return propsMap;
	}
	/**
	 * 不使用spring boot預設方式建立的DefaultKafkaConsumerFactory，重新定義建立方式
	 * @return
	 */
	public ConsumerFactory<String, String> consumerFactory() {
		return new DefaultKafkaConsumerFactory<>(consumerConfigs());
	}

	@Bean
	public KafkaListenerContainerFactory<ConcurrentMessageListenerContainer<String, String>> kafkaListenerContainerFactory() {
		ConcurrentKafkaListenerContainerFactory<String, String> factory = new ConcurrentKafkaListenerContainerFactory<>();
		factory.setConsumerFactory(consumerFactory());
		factory.setConcurrency(concurrency);
		factory.setMissingTopicsFatal(false);
		factory.getContainerProperties().setPollTimeout(1500);
		factory.setBatchListener(true);
		return factory;
	}

}