kafka学习 -- 客户端Consumer API学习

写在前面

这里我会总结一下，Springboot 集成 spring-kafka中，consumer 的相关配置，Api

这里的东西，比 Producer 稍微多一些

集成相关配置

server:
  port: 9000
spring:
  kafka:
    bootstrap-servers: 192.168.1.74:9092
    consumer:
      group-id: group_id
      # 手动提交
      enable-auto-commit: false
      auto-offset-reset: earliest
      key-deserializer: org.apache.kafka.common.serialization.StringDeserializer
      value-deserializer: org.apache.kafka.common.serialization.StringDeserializer
      properties:
        session.timeout.ms: 60000
    listener:
      type: batch
      log-container-config: false
      concurrency: 3
      # 手动提交
      ack-mode: manual_immediate

一、@KafkaListener

Spring Kafka 集成Kafka，消息的监听者配置，使用特别简单，只有一个注解即可实现监听

虽然只有一个注解配置，需要注意消息的序列化，以及相关监听处理

二、代码示例

示例一

@KafkaListener(topics = "users", groupId = "group_id")
    public void consume(String message, Acknowledgment acknowledgment) throws IOException {
        try {
            logger.info(String.format("#### -> Consumed message -> %s", message));
        } catch (Exception e) {
            logger.error(e.getMessage(), e);
        } finally {
            // 手动提交 offset
            acknowledgment.acknowledge();
        }
    }

示例二

import com.common.Bar2;
import com.common.Foo2;
import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.kafka.annotation.KafkaHandler;
import org.springframework.kafka.annotation.KafkaListener;
import org.springframework.stereotype.Component;

/**
 * 这里定义了消费者组，和多个 topic 的对应
 *
 * @author Gary Russell
 * @since 5.1
 */
@Component
@KafkaListener(id = "multiGroup", topics = {"foos", "bars", "test"})
public class MultiMethods {

    private final Logger logger = LoggerFactory.getLogger(MultiMethods.class);

    @KafkaHandler
    public void foo(Foo2 foo) {
        System.out.println("Received: " + foo);
    }

    @KafkaHandler
    public void bar(Bar2 bar) {
        System.out.println("Received: " + bar);
    }

    @KafkaHandler(isDefault = true)
    public void unknown(Object object) {
        System.out.println("Received unknown: " + object);
    }


    @KafkaHandler
    public void tests(ConsumerRecord record) {
        logger.info("Received -> key :{} ", record.key());
    }

}

三、更多Kafka,，客户端、服务端，监控可参考下文

• ​​kafka学习 – kafka connect​​
• ​​kafka学习 – 客户端Consumer API学习​​
• ​​kafka学习 – 客户端Producer API学习​​
• ​​kafka学习 – 服务端命令学习​​
• ​​Springboot集成Kafka​​