一.使用背景
现在很多公司的业务都是使用分布式系统,使用分布式系统就面临着不同系统间的消息传递,现在市面上比较流行的消息中间件有,ActiveMQ,RabbitMQ,RocketMQ,kafka等等，下面就来讲解一些springboot项目中集成kafka以及使用。
二.springboot项目中使用kafka
1.在maven中添加依赖
<dependency>
<groupId>org.springframework.kafka</groupId>
<artifactId>spring-kafka</artifactId>
<version>1.1.1.RELEASE</version>
</dependency>
2.在application.properties中添加配置
#============== kafka 消费端配置===================
kafka.consumer.zookeeper.connect=127.0.0.1:2181
kafka.consumer.servers=127.0.0.1:9092
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 生产端配置===================
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
3.kafka生产端代码
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
代码如下
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 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.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
return props;
}
public ProducerFactory<String, String> producerFactory() {
return new DefaultKafkaProducerFactory<>(producerConfigs());
}
@Bean
public KafkaTemplate<String, String> kafkaTemplate() {
return new KafkaTemplate<String, String>(producerFactory());
}
}
4）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);
}
}
}
4.消费端代码
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
代码如下:
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<ConcurrentMessageListenerContainer<String, String>> kafkaListenerContainerFactory() {
ConcurrentKafkaListenerContainerFactory<String, String> factory = new ConcurrentKafkaListenerContainerFactory<>();
factory.setConsumerFactory(consumerFactory());
factory.setConcurrency(concurrency);
factory.getContainerProperties().setPollTimeout(1500);
return factory;
}
public ConsumerFactory<String, String> consumerFactory() {
return new DefaultKafkaConsumerFactory<>(consumerConfigs());
}
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);
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());
}
}
