use kotlinx.serialization instead of ObjectMapper in kafka producer

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

@@ -2,7 +2,6 @@ package com.example.demo.config
 
 import com.example.demo.services.kafka.Producer
 import com.example.demo.services.kafka.ProducerImpl
-import com.fasterxml.jackson.databind.ObjectMapper
 import org.apache.kafka.clients.producer.ProducerConfig
 import org.apache.kafka.common.serialization.StringSerializer
 import org.springframework.beans.factory.annotation.Autowired
@@ -37,9 +36,7 @@ class KafkaProducerConfig(
     @Bean
     fun producer(
         @Autowired kafkaTemplate: KafkaTemplate<String, Any>,
-        @Autowired objectMapper: ObjectMapper
     ): Producer = ProducerImpl(
         kafkaTemplate,
-        objectMapper,
     )
 }

src/main/kotlin/com/example/demo/models/City.kt

@@ -1,7 +1,7 @@
 package com.example.demo.models
 
-import com.example.demo.models.serializables.OffsetDateTimeSerialization
-import com.example.demo.models.serializables.UuidSerialization
+import com.example.demo.services.serializables.OffsetDateTimeSerialization
+import com.example.demo.services.serializables.UuidSerialization
 import kotlinx.serialization.Serializable
 import org.springframework.data.annotation.Id
 import org.springframework.data.relational.core.mapping.Column

src/main/kotlin/com/example/demo/models/Product.kt

@@ -1,8 +1,8 @@
 package com.example.demo.models
 
 
-import com.example.demo.models.serializables.OffsetDateTimeSerialization
-import com.example.demo.models.serializables.UuidSerialization
+import com.example.demo.services.serializables.OffsetDateTimeSerialization
+import com.example.demo.services.serializables.UuidSerialization
 import com.example.demo.utils.roundTo
 import kotlinx.serialization.Serializable
 import org.springframework.data.annotation.Id

src/main/kotlin/com/example/demo/services/kafka/ProducerImpl.kt

@@ -2,7 +2,8 @@ package com.example.demo.services.kafka
 
 import com.example.demo.models.Product
 import com.example.demo.services.kafka.dto.ProductDto
-import com.fasterxml.jackson.databind.ObjectMapper
+import kotlinx.serialization.json.Json
+import kotlinx.serialization.json.encodeToJsonElement
 import org.springframework.kafka.core.KafkaTemplate
 import org.springframework.kafka.support.KafkaHeaders
 import org.springframework.messaging.Message
@@ -12,11 +13,12 @@ import org.springframework.stereotype.Service
 @Service
 class ProducerImpl(
     private val kafkaTemplate: KafkaTemplate<String, Any>,
-    private val objectMapper: ObjectMapper
 ): Producer {
     override fun produceProductInfo(topicName: String, product: Product) {
+
+        val serializedProduct = Json.encodeToJsonElement(ProductDto(product))
         val message: Message<String> = MessageBuilder
-            .withPayload(objectMapper.writeValueAsString(ProductDto(product)))
+            .withPayload(serializedProduct.toString())
             .setHeader(KafkaHeaders.TOPIC, topicName)
             .setHeader("X-Custom-Header", "some-custom-header")
             .build()

src/main/kotlin/com/example/demo/services/kafka/dto/ProductDto.kt

@@ -2,25 +2,18 @@ package com.example.demo.services.kafka.dto
 
 import com.example.demo.models.Product
 import com.example.demo.services.kafka.exceptions.InvalidArgumentException
-import com.fasterxml.jackson.annotation.JsonProperty
+import kotlinx.serialization.Serializable
 import java.time.format.DateTimeFormatter
 
+@Serializable
 data class ProductDto(
-    @JsonProperty("id")
     val id: Long,
-    @JsonProperty("guid")
     val guid: String,
-    @JsonProperty("name")
     val name: String,
-    @JsonProperty("description")
     val description: String?,
-    @JsonProperty("price")
     val price: Long,
-    @JsonProperty("createdAt")
     val createdAt: String,
-    @JsonProperty("updatedAt")
     val updatedAt: String?,
-    @JsonProperty("deletedAt")
     val deletedAt: String?,
 ) {
     @Throws(InvalidArgumentException::class)

src/main/kotlin/com/example/demo/services/serializables/OffsetDateTimeSerialization.kt

@@ -1,4 +1,4 @@
-package com.example.demo.models.serializables
+package com.example.demo.services.serializables
 
 import kotlinx.serialization.KSerializer
 import kotlinx.serialization.descriptors.PrimitiveKind

src/main/kotlin/com/example/demo/services/serializables/UuidSerialization.kt

@@ -1,4 +1,4 @@
-package com.example.demo.models.serializables
+package com.example.demo.services.serializables
 
 import kotlinx.serialization.KSerializer
 import kotlinx.serialization.descriptors.PrimitiveKind

src/test/kotlin/com/example/demo/services/kafka/ProducerImplTest.kt

@@ -3,7 +3,7 @@ package com.example.demo.services.kafka
 import com.example.demo.BaseUnitTest
 import com.example.demo.models.Product
 import com.example.demo.services.kafka.dto.ProductDto
-import com.fasterxml.jackson.databind.ObjectMapper
+import kotlinx.serialization.json.Json
 import org.junit.runner.RunWith
 import org.mockito.kotlin.argumentCaptor
 import org.mockito.kotlin.doReturn
@@ -28,9 +28,6 @@ class ProducerImplTest: BaseUnitTest() {
     @Autowired
     private lateinit var producerImpl: ProducerImpl
 
-    @Autowired
-    private lateinit var objectMapper: ObjectMapper
-
     @MockBean
     private lateinit var kafkaTemplate: KafkaTemplate<String, Any>
 
@@ -58,7 +55,7 @@ class ProducerImplTest: BaseUnitTest() {
         assertEquals(1, captor.allValues.count())
         val actualArgument = captor.firstValue
 
-        val actualProductDto = objectMapper.readValue(actualArgument.payload, ProductDto::class.java)
+        val actualProductDto = Json.decodeFromString<ProductDto>(actualArgument.payload)
         assertEquals(product.id, actualProductDto.id)
         assertEquals(product.guid.toString(), actualProductDto.guid)
         assertEquals(topic, actualArgument.headers[KafkaHeaders.TOPIC])