Kafka主题在spring boot启动后未在远程Kafka上自动创建（并在本地Kafka服务器上创建）

Question

1）我在机器上启动Kafka

2）我用配置启动Spring Boot服务器：

@Bean
public NewTopic MyTopic() {
    return new NewTopic("my-topic", 5, (short) 1);
}

@Bean
public ProducerFactory<String, byte[]> greetingProducerFactory() {
    Map<String, Object> configProps = new HashMap<>();
    configProps.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, "localhost:9092");
    configProps.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
    configProps.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, ByteArraySerializer.class);
    return new DefaultKafkaProducerFactory<>(configProps);
}

@Bean
public KafkaTemplate<String, byte[]> unpMessageKafkaTemplate() {
    return new KafkaTemplate<>(greetingProducerFactory());
}

12:35:09.880 [                  main] [INFO ]    o.a.k.clients.admin.AdminClientConfig: [] AdminClientConfig values: 
    bootstrap.servers = [localhost:9092]

@Bean
public KafkaAdmin admin() {
    Map<String, Object> configs = new HashMap<>();
    configs.put(AdminClientConfig.BOOTSTRAP_SERVERS_CONFIG, "remote_host:9092");
    return new KafkaAdmin(configs);
}

1）为什么会发生这种情况？

2）我必须创建kafkaadmin吗？为什么不需要本地Kafka？

埃德迪特

spring:
  kafka:
    bootstrap-servers: remote:9092
    producer:
      key-serializer: org.apache.kafka.common.serialization.StringDeserializer
      value-serializer: org.apache.kafka.common.serialization.ByteArraySerializer

@Configuration
public class KafkaTopicConfig {

    @Value("${response.topics.topicName}")
    private String topicName;

    @Bean
    public NewTopic responseTopic() {
        return new NewTopic(topicName, 5, (short) 1);
    }

}

bootstrap.servers = [remote:9092]
    client.id = 
    connections.max.idle.ms = 300000
    metadata.max.age.ms = 300000
    metric.reporters = []
    metrics.num.samples = 2
    metrics.recording.level = INFO
    metrics.sample.window.ms = 30000
    receive.buffer.bytes = 65536

Answer 1

KafkaAdmin是kafka spring对象，它在spring上下文中查找NewTopic对象并创建它们。如果你没有一个KafkaAdmin，就不会发生任何创造。您可以显式地创建KafkaAdmin（如代码段所示），也可以通过spring kafka配置属性间接地对其创建进行排序。

KafkaAdmin是一个很好的，它与生产或消费无关，适用于您的应用程序代码的主题。

编辑

spring:
  kafka:
    bootstrap-servers: remote:9092

和

2019-03-21 09:18:18.354  INFO 58301 --- [           main] o.a.k.clients.admin.AdminClientConfig    
        : AdminClientConfig values: 
    bootstrap.servers = [remote:9092]
    ...