CODEWITHSUNDEEP
kotlinapache-kafkajacksonspring-cloud-streamcloudevents
user3806586
user3806586

Reputation: 53

CloudEvent Jackson deserialize to POJO

I am trying to consume messages wrapped by CloudEvents.V1 in Kotlin

I checked on documentation (doc) and applied the same idea as in Java.

My event is built as:

CloudEventBuilder.v1()
  .withId(UUID.randomUUID().toString())
  .withSource(URI.create(EVENT_SOURCE))
  .withType(configs.mapTypes[topic])
  .withTime(OffsetDateTime.now())
  .withData(objectMapper.writeValueAsBytes(result))
  .withDataContentType("application/json")
  .build()

My consumer properties are as follows:

val props = Properties()
        props[ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG] = KAFKA.bootstrapServers
        props[ConsumerConfig.GROUP_ID_CONFIG] = groupId
        props[ConsumerConfig.AUTO_OFFSET_RESET_CONFIG] = OffsetResetStrategy.EARLIEST.name.lowercase()
        props[ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG] = StringDeserializer::class.java
        props[ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG] = CloudEventDeserializer::class.java
        return props

My dataclass:

data class Test(
    val id: String,
    val score: Double
)

When I try to convert the data to an object using jackson objectmapper and CloudEventUtils.mapData as follows:

val MAPPER: ObjectMapper = jacksonObjectMapper()
            .enable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS)
            .disable(SerializationFeature.WRITE_DATE_TIMESTAMPS_AS_NANOSECONDS)
            .registerModule(JavaTimeModule())

val data = CloudEventUtils.mapData(
                message[0],
                PojoCloudEventDataMapper.from(MAPPER, Test::class.java)
            )

I get the error:

errorType: DATA_CONVERSION

detailMessage: Error while trying to convert data from class com.fasterxml.jackson.databind.JsonNode to [simple type, class com.trendyol.mergetopicsstream.fixtures.Test]

cause: java.lang.IllegalArgumentException: Cannot construct instance of `com.trendyol.mergetopicsstream.fixtures.Test` (although at least one Creator exists): no String-argument constructor/factory method to deserialize from String value ('{"id":"Zagxn","score":0.354854009767147}')
 at [Source: UNKNOWN; byte offset: #UNKNOWN]

Upvotes: 0

Views: 1187

Answers (0)

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