SpringBoot集成Kafka的步骤

  org.springframework.boot
  spring-boot-starter-web


  org.springframework.kafka
  spring-kafka



  com.google.code.gson
  gson

spring:
 kafka:
  bootstrap-servers: 192.168.25.6:9092 #bootstrap-servers：连接kafka的地址，多个地址用逗号分隔
  consumer:
   group-id: myGroup
   enable-auto-commit: true
   auto-commit-interval: 100ms
   properties:
    session.timeout.ms: 15000
   key-deserializer: org.apache.kafka.common.serialization.StringDeserializer
   value-deserializer: org.apache.kafka.common.serialization.StringDeserializer
   auto-offset-reset: earliest
  producer:
   retries: 0 #若设置大于0的值，客户端会将发送失败的记录重新发送
   batch-size: 16384 #当将多个记录被发送到同一个分区时， Producer 将尝试将记录组合到更少的请求中。这有助于提升客户端和服务器端的性能。这个配置控制一个批次的默认大小（以字节为单位）。16384是缺省的配置
   buffer-memory: 33554432 #Producer 用来缓冲等待被发送到服务器的记录的总字节数，33554432是缺省配置
   key-serializer: org.apache.kafka.common.serialization.StringSerializer #关键字的序列化类
   value-serializer: org.apache.kafka.common.serialization.StringSerializer #值的序列化类

/**
 * @author johnny
 * @create 2020-09-23 上午9:21
 **/
@Data
public class Message {


  private Long id;

  private String msg;

  private Date sendTime;
}

@Component
@Slf4j
public class KafkaSender {

  private final KafkaTemplate kafkaTemplate;

  //构造器方式注入 kafkaTemplate
  public KafkaSender(KafkaTemplate kafkaTemplate) {
    this.kafkaTemplate = kafkaTemplate;
  }

  private Gson gson = new GsonBuilder().create();

  public void send(String msg) {
    Message message = new Message();

    message.setId(System.currentTimeMillis());
    message.setMsg(msg);
    message.setSendTime(new Date());
    log.info("【++++++++++++++++++ message ：{}】", gson.toJson(message));
    //对 topic = hello2 的发送消息
    kafkaTemplate.send("hello2",gson.toJson(message));
  }

}

@Component
@Slf4j
public class KafkaConsumer {


  @KafkaListener(topics = {"hello2"})
  public void listen(ConsumerRecord<?, ?> record) {

    Optional.ofNullable(record.value())
        .ifPresent(message -> {
          log.info("【+++++++++++++++++ record = {} 】", record);
          log.info("【+++++++++++++++++ message = {}】", message);
        });
  }

}

@RestController
@Slf4j
public class TestController {


  @Autowired
  private KafkaSender kafkaSender;


  @GetMapping("sendMessage/{msg}")
  public void sendMessage(@PathVariable("msg") String msg){
    kafkaSender.send(msg);
  }
}