Spring Boot Kafka

Kafka的核心概念，以及如何保证高可用性、可靠性、顺序性等问题这里就不赘述了，本文只记录操作示例。

依赖配置

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

application.yml

spring:
  kafka:
    bootstrap-servers: localhost:9092
    consumer:
      group-id: message # consumer group 消费者群组
      auto-offset-reset: latest # 当各分区下有已提交的offset时，从提交的offset开始消费；无提交的offset时，消费新产生的该分区下的数据

KafkaProducerConfig

存储Java类MessageForm对象,需要自行替换

@Configuration
public class KafkaProducerConfig {

    @Value("${spring.kafka.bootstrap-servers}")
    private String bootstrapServers;
    

    @Bean
    public Map<String, Object> producerConfigs() {
        Map<String, Object> props = new HashMap<>();
        props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
        props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
        props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, JsonSerializer.class);

        return props;
    }

    @Bean
    public ProducerFactory<String, MessageForm> producerFactory() {
        return new DefaultKafkaProducerFactory<>(producerConfigs());
    }

    @Bean
    public KafkaTemplate<String, MessageForm> kafkaTemplate() {
        return new KafkaTemplate<>(producerFactory());
    }
}

KafkaConsumerConfig

配置类上需要@EnableKafka注释才能在Spring托管Bean上检测@KafkaListener注解。

@EnableKafka
@Configuration
public class KafkaConsumerConfig {
    @Value("${spring.kafka.bootstrap-servers}")
    private String bootstrapServers;

    @Bean
    public Map<String, Object> consumerConfigs() {
        Map<String, Object> props = new HashMap<>();
        props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, bootstrapServers);
        props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
        props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, JsonDeserializer.class);

        return props;
    }

    @Bean
    public ConsumerFactory<String, MessageForm> consumerFactory() {
        return new DefaultKafkaConsumerFactory<>(consumerConfigs(), new StringDeserializer(),
                new JsonDeserializer<>(MessageForm.class));
    }

    @Bean
    public ConcurrentKafkaListenerContainerFactory<String, MessageForm> kafkaListenerContainerFactory() {
        ConcurrentKafkaListenerContainerFactory<String, MessageForm> factory =
                new ConcurrentKafkaListenerContainerFactory<>();
        factory.setConsumerFactory(consumerFactory());

        return factory;
    }
}

KafkaMessageListener

在KafkaConsumerConfig中我们配置了ConsumerFactory和KafkaListenerContainerFactory。当这两个Bean成功注册到Spring IOC容器中后，我们便可以使用@KafkaListener注解来监听消息了。

@Component
public class KafkaMessageListener {

    @Resource
    private MessageService messageServiceImpl;

    @KafkaListener(topics="message",groupId = "consumer")
    public void listen(MessageForm messageForm){
        messageServiceImpl.message(messageForm);
    }
}