卡夫卡没有连接得到以下问题答案

【问题标题】：Kafka not connecting getting below issue卡夫卡没有连接得到以下问题
【发布时间】：2021-11-06 08:53:36
【问题描述】：

2021-09-09 21:42:40.039  WARN 14636 --- [ntainer#0-0-C-1] org.apache.kafka.clients.NetworkClient   : [Consumer clientId=consumer-mygroup-1, groupId=mygroup] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available.
2021-09-09 21:42:40.039  WARN 14636 --- [ntainer#0-0-C-1] org.apache.kafka.clients.NetworkClient   : [Consumer clientId=consumer-mygroup-1, groupId=mygroup] Bootstrap broker localhost:9092 (id: -1 rack: null) disconnected
2021-09-09 21:42:41.778  WARN 14636 --- [ad | producer-1] org.apache.kafka.clients.NetworkClient   : [Producer clientId=producer-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available.
2021-09-09 21:42:41.779  WARN 14636 --- [ad | producer-1] org.apache.kafka.clients.NetworkClient   : [Producer clientId=producer-1] Bootstrap broker localhost:9092 (id: -1 rack: null) disconnected
2021-09-09 21:42:43.001  WARN 14636 --- [ntainer#0-0-C-1] org.apache.kafka.clients.NetworkClient   : [Consumer clientId=consumer-mygroup-1, groupId=mygroup] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available.
2021-09-09 21:42:43.002  WARN 14636 --- [ntainer#0-0-C-1] org.apache.kafka.clients.NetworkClient   : [Consumer clientId=consumer-mygroup-1, groupId=mygroup] Bootstrap broker localhost:9092 (id: -1 rack: null) disconnected
2021-09-09 21:42:44.634  WARN 14636 --- [ad | producer-1] org.apache.kafka.clients.NetworkClient   : [Producer clientId=producer-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available.
2021-09-09 21:42:44.634  WARN 14636 --- [ad | producer-1] org.apache.kafka.clients.NetworkClient   : [Producer clientId=producer-1] Bootstrap broker localhost:9092 (id: -1 rack: null) disconnected
2021-09-09 21:42:45.908  WARN 14636 --- [ntainer#0-0-C-1] org.apache.kafka.clients.NetworkClient   : [Consumer clientId=consumer-mygroup-1, groupId=mygroup] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available.
2021-09-09 21:42:45.908  WARN 14636 --- [ntainer#0-0-C-1] org.apache.kafka.clients.NetworkClient   : [Consumer clientId=consumer-mygroup-1, groupId=mygroup]

代码

@Service
public class KafKaConsumerService {
    private final Logger logger = 
            LoggerFactory.getLogger(KafKaConsumerService.class);
 
    @KafkaListener(topics="mytopic", groupId="mygroup")
    public void consumeFromTopic(String message) {
        System.out.println("Consummed message "+message);
    }

}

    public class KafKaProducerService {
    private static final Logger logger = 
            LoggerFactory.getLogger(KafKaProducerService.class);
     
    public static final String topic = "mytopic";
      
      @Autowired 
      private KafkaTemplate<String, String> kafkaTemp;
      
      public void publishToTopic(String message) {
          System.out.println("Publishing to topic "+topic);
          this.kafkaTemp.send(topic, message);
      }
}

属性

spring.kafka.consumer.bootstrap-servers=localhost:9092
spring.kafka.consumer.group-id=mygroup
spring.kafka.consumer.auto-offset-reset=earliest
spring.kafka.consumer.key-deserializer=org.apache.kafka.common.serialization.StringDeserializer
spring.kafka.consumer.value-deserializer=org.apache.kafka.common.serialization.StringDeserializer

spring.kafka.producer.bootstrap-servers=localhost:9092
spring.kafka.producer.key-deserializer = org.apache.kafka.common.serialization.StringDeserializer
spring.kafka.producer.value-deserializer = org.apache.kafka.common.serialization.StringDeserializer

【问题讨论】：

你的 kafka 是否在本地的 9092 端口运行？你能确认一下

标签： java spring spring-boot apache-kafka kafka-consumer-api

【解决方案1】：

由于以下 Apache-Kafka 配置，您收到此警告

KAFKA_AUTO_CREATE_TOPICS_ENABLE: 'false'

这意味着在 Spring Boot 启动时消费者尝试收听/使用来自 mytopic 的消息，但它实际上不存在。

请先创建主题或将以上配置更改为

KAFKA_AUTO_CREATE_TOPICS_ENABLE: 'true'

【讨论】：