Send in multiple topic kafka sink with flink

Question

I have a data stream like :

DataStream[myTuple(topic, value)]

And I wanted to send a specific value in the associated topic.

So I try to do somthing like that :

new FlinkKafkaProducer010[myTuple](
  "default_topic",
  new KeyedSerializationSchema[myTuple](){
    override def getTargetTopic(element: myTuple): String = element.topic
    override def serializeKey(element: myTuple): Array[Byte] = null
    override def serializeValue(element: myTuple): Array[Byte] = new SimpleStringSchema().serialize(element.value)
  },
  properties)

but it doesn't work and I have this warning:

WARN  org.apache.flink.streaming.connectors.kafka.FlinkKafkaProducerBase  - Overwriting the 'key.serializer' is not recommended
WARN  org.apache.flink.streaming.connectors.kafka.FlinkKafkaProducerBase  - Overwriting the 'value.serializer' is not recommended

I have no idea how to do it, by another way. thx for your help.

Answer 1

You probably set key.serializer and value.serializer in your properties. You should not do this, cause this way you overwrite serializers ( ByteArraySerializer s) used internally by Flink. Remove those properties and your code should work.