本文介绍如何在springboot项目中集成kafka收发message。
1、先解决依赖
springboot相关的依赖我们就不提了,和kafka相关的只依赖一个spring-kafka集成包
<dependency> <groupId>org.springframework.kafkagroupId> <artifactId>spring-kafkaartifactId> <version>1.1.1.RELEASEversion> dependency>
这里我们先把配置文件展示一下
#============== kafka ===================
kafka.consumer.zookeeper.connect=10.93.21.21:2181
kafka.consumer.servers=10.93.21.21:9092
kafka.consumer.enable.auto.commit=true
kafka.consumer.session.timeout=6000
kafka.consumer.auto.commit.interval=100
kafka.consumer.auto.offset.reset=latest
kafka.consumer.topic=test
kafka.consumer.group.id=test
kafka.consumer.concurrency=10
kafka.producer.servers=10.93.21.21:9092
kafka.producer.retries=0
kafka.producer.batch.size=4096
kafka.producer.linger=1
kafka.producer.buffer.memory=40960
2、Configuration:Kafka producer
1)通过@Configuration、@EnableKafka,声明Config并且打开KafkaTemplate能力。
2)通过@Value注入application.properties配置文件中的kafka配置。
3)生成bean,@Bean
package com.kangaroo.sentinel.collect.configuration; 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 KafkaProducerConfig { @Value("${kafka.producer.servers}") private String servers; @Value("${kafka.producer.retries}") private int retries; @Value("${kafka.producer.batch.size}") private int batchSize; @Value("${kafka.producer.linger}") private int linger; @Value("${kafka.producer.buffer.memory}") private int bufferMemory; public MapproducerConfigs() { Map 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.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class); props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class); return props; } public ProducerFactory producerFactory() { return new DefaultKafkaProducerFactory<>(producerConfigs()); } @Bean public KafkaTemplate kafkaTemplate() { return new KafkaTemplate (producerFactory()); } }
实验我们的producer,写一个Controller。想topic=test,key=key,发送消息message
package com.kangaroo.sentinel.collect.controller; import com.kangaroo.sentinel.common.response.Response; import com.kangaroo.sentinel.common.response.ResultCode; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.kafka.core.KafkaTemplate; import org.springframework.web.bind.annotation.*; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; @RestController @RequestMapping("/kafka") public class CollectController { protected final Logger logger = LoggerFactory.getLogger(this.getClass()); @Autowired private KafkaTemplate kafkaTemplate; @RequestMapping(value = "/send", method = RequestMethod.GET) public Response sendKafka(HttpServletRequest request, HttpServletResponse response) { try { String message = request.getParameter("message"); logger.info("kafka的消息={}", message); kafkaTemplate.send("test", "key", message); logger.info("发送kafka成功."); return new Response(ResultCode.SUCCESS, "发送kafka成功", null); } catch (Exception e) { logger.error("发送kafka失败", e); return new Response(ResultCode.EXCEPTION, "发送kafka失败", null); } } }
3、configuration:kafka consumer
1)通过@Configuration、@EnableKafka,声明Config并且打开KafkaTemplate能力。
2)通过@Value注入application.properties配置文件中的kafka配置。
3)生成bean,@Bean
package com.kangaroo.sentinel.collect.configuration; 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; import java.util.HashMap; import java.util.Map; @Configuration @EnableKafka public class KafkaConsumerConfig { @Value("${kafka.consumer.servers}") private String servers; @Value("${kafka.consumer.enable.auto.commit}") private boolean enableAutoCommit; @Value("${kafka.consumer.session.timeout}") private String sessionTimeout; @Value("${kafka.consumer.auto.commit.interval}") private String autoCommitInterval; @Value("${kafka.consumer.group.id}") private String groupId; @Value("${kafka.consumer.auto.offset.reset}") private String autoOffsetReset; @Value("${kafka.consumer.concurrency}") private int concurrency; @Bean public KafkaListenerContainerFactory> kafkaListenerContainerFactory() { ConcurrentKafkaListenerContainerFactory factory = new ConcurrentKafkaListenerContainerFactory<>(); factory.setConsumerFactory(consumerFactory()); factory.setConcurrency(concurrency); factory.getContainerProperties().setPollTimeout(1500); return factory; } public ConsumerFactory consumerFactory() { return new DefaultKafkaConsumerFactory<>(consumerConfigs()); } public Map consumerConfigs() { Map 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); propsMap.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class); propsMap.put(ConsumerConfig.GROUP_ID_CONFIG, groupId); propsMap.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, autoOffsetReset); return propsMap; } @Bean public Listener listener() { return new Listener(); } }
new Listener()生成一个bean用来处理从kafka读取的数据。Listener简单的实现demo如下:只是简单的读取并打印key和message值
@KafkaListener中topics属性用于指定kafka topic名称,topic名称由消息生产者指定,也就是由kafkaTemplate在发送消息时指定。
package com.kangaroo.sentinel.collect.configuration; import org.apache.kafka.clients.consumer.ConsumerRecord; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.kafka.annotation.KafkaListener; public class Listener { protected final Logger logger = LoggerFactory.getLogger(this.getClass()); @KafkaListener(topics = {"test"}) public void listen(ConsumerRecord, ?> record) { logger.info("kafka的key: " + record.key()); logger.info("kafka的value: " + record.value().toString()); } }
tips:
1)我没有介绍如何安装配置kafka,配置kafka时最好用完全bind网络ip的方式,而不是localhost或者127.0.0.1
2)最好不要使用kafka自带的zookeeper部署kafka,可能导致访问不通。
3)理论上consumer读取kafka应该是通过zookeeper,但是这里我们用的是kafkaserver的地址,为什么没有深究。
4)定义监听消息配置时,GROUP_ID_CONFIG配置项的值用于指定消费者组的名称,如果同组中存在多个监听器对象则只有一个监听器对象能收到消息。