spring boot使用kafka

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介绍：之前的文章里面讲过了怎么部署kafka，这边文章就介绍怎么使用spring boot 使用kafka

第一步：加入相关架包

<dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
   <groupId>org.springframework.kafka</groupId>
   <artifactId>spring-kafka</artifactId>
</dependency>

第二步：application.yml配置文件

//集群brokers以逗号隔开
kafka:
  brokers: 192.168.0.117:9092
  groupid: test-group

第三步：生产消息配置类

package com.example.config;
 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;
 import java.util.LinkedHashMap;
 import java.util.Map;
 /**
 * @Author: 凉白开不加冰
 * @Version: 0.0.1V
 * @Date: 2019/1/9
 * @Description: kafka生产配置
 **/
 @Configuration
 @EnableKafka
 public class KafkaProducerConfig {
     @Value("${kafka.brokers}")
     private String brokers;
     public Map producerConfigs() {
         Map props = new LinkedHashMap<>();
         props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, brokers);
         props.put(ProducerConfig.RETRIES_CONFIG, 0);
         props.put(ProducerConfig.BATCH_SIZE_CONFIG, 4096);
         props.put(ProducerConfig.LINGER_MS_CONFIG, 1);
         props.put(ProducerConfig.BATCH_SIZE_CONFIG, 40960);
         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());
     }
 } 

第四步：消费消息配置类

package com.example.config;

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.LinkedHashMap;
import java.util.Map;

/**
 * @Author: 凉白开不加冰
 * @Version: 0.0.1V
 * @Date: 2019/1/9
 * @Description: kafka消费者配置
 **/
@Configuration
@EnableKafka
public class KafkaConsumerConfig {
    @Value("${kafka.brokers}")
    private String brokers;

    @Value("${kafka.groupid}")
    private String groupid;

    public Map<String,Object> consumerConfigs(){
        Map<String,Object> props = new LinkedHashMap<>();
        props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG,brokers);
        props.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG,false);
        props.put(ConsumerConfig.AUTO_COMMIT_INTERVAL_MS_CONFIG,"100");
        props.put(ConsumerConfig.SESSION_TIMEOUT_MS_CONFIG,"15000");
        //注意此处反序列化，别搞错了，跟生产消息不一样
        props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG,StringDeserializer.class);
        props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG,StringDeserializer.class);
        props.put(ConsumerConfig.GROUP_ID_CONFIG,groupid);
        props.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG,"latest");
        return props;
    }

    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(3);
        factory.getContainerProperties().setPollTimeout(3000);
        return factory;
    }
}

第五步：消费消息

package com.example.consumer;

import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.springframework.kafka.annotation.KafkaListener;
import org.springframework.stereotype.Component;

import java.util.Optional;

/**
 * @Author: 凉白开不加冰
 * @Version: 0.0.1V
 * @Date: 2019/1/9
 * @Description: 消费消息
 **/
@Component
public class KafkaConsumer {
    /**
     * @Author: hualao
     * @Date:   2019/1/9 11:25
     * @Description: topics中填写在服务器上创建的topic即可
    **/
    @KafkaListener(topics = {"test"})
    public void consumer(ConsumerRecord<?,?> record){
        Optional<?> kafkaMessage = Optional.ofNullable(record.value());
        if(kafkaMessage.isPresent()){
            System.out.println(kafkaMessage.get());
        }
    }
}

第六步：生产消息

package com.example.producer;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.kafka.core.KafkaTemplate;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;

/**
 * @Author: 凉白开不加冰
 * @Version: 0.0.1V
 * @Date: 2019/1/9
 * @Description: 生产消息
 **/
@RestController
public class KafkaProducer {

    @Autowired
    private KafkaTemplate kafkaTemplate;

    @RequestMapping("send")
    public void send(){
        //发送消息到test topic
        kafkaTemplate.send("test", LocalDateTime.now().format(DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.SSS"))+"");
    }
}

如果生产消息时报以下错误

Expiring 2 record(s) for zlikun_topic-3: 30042 ms has passed since batch creation plus linger time

需要修改kafka配置文件server.properties,在属性文件里加上host.name=服务器ip