add KafkaConsumerConfig configuration

src/main/kotlin/com/example/demo/config/KafkaConsumerConfig.kt

@@ -0,0 +1,65 @@
+package com.example.demo.config
+
+import com.example.demo.services.kafka.dto.CityCreateDto
+import org.apache.kafka.clients.consumer.ConsumerConfig
+import org.apache.kafka.common.serialization.StringDeserializer
+import org.springframework.beans.factory.annotation.Value
+import org.springframework.context.annotation.Bean
+import org.springframework.context.annotation.Configuration
+import org.springframework.kafka.config.ConcurrentKafkaListenerContainerFactory
+import org.springframework.kafka.core.ConsumerFactory
+import org.springframework.kafka.core.DefaultKafkaConsumerFactory
+import org.springframework.kafka.support.converter.RecordMessageConverter
+import org.springframework.kafka.support.converter.StringJsonMessageConverter
+import org.springframework.kafka.support.mapping.DefaultJackson2JavaTypeMapper
+import org.springframework.kafka.support.mapping.Jackson2JavaTypeMapper
+
+@Configuration
+class KafkaConsumerConfig(
+    @Value("\${kafka.bootstrap-servers}")
+    val servers: String,
+    @Value("\${kafka.consumer.group-id}")
+    val consumerGroup: String,
+) {
+//    @Bean
+//    fun consumer(@Autowired cityService: CityService): Consumer = Consumer(
+//        cityService = cityService,
+//    )
+
+    @Bean
+    fun consumerFactory(): ConsumerFactory<String, String> {
+        val configs = HashMap<String, Any>()
+        configs[ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG] = servers
+        configs[ConsumerConfig.GROUP_ID_CONFIG] = consumerGroup
+        configs[ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG] = StringDeserializer::class.java
+        configs[ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG] = StringDeserializer::class.java
+
+        return DefaultKafkaConsumerFactory(configs)
+    }
+
+    @Bean
+    fun kafkaListenerContainerFactory(): ConcurrentKafkaListenerContainerFactory<String, String> {
+        val factory = ConcurrentKafkaListenerContainerFactory<String, String>()
+        factory.consumerFactory = consumerFactory()
+        factory.setRecordMessageConverter(recordMessageConverter())
+
+        return factory
+    }
+
+    @Bean
+    fun recordMessageConverter(): RecordMessageConverter {
+        val converter = StringJsonMessageConverter()
+
+        val typeMapper = DefaultJackson2JavaTypeMapper()
+        typeMapper.typePrecedence = Jackson2JavaTypeMapper.TypePrecedence.TYPE_ID
+        typeMapper.addTrustedPackages("com.baeldung.spring.kafka")
+
+        val mappings: MutableMap<String, Class<*>> = HashMap()
+        mappings["city"] = CityCreateDto::class.java
+        typeMapper.idClassMapping = mappings
+
+        converter.typeMapper = typeMapper
+
+        return converter
+    }
+}