kafka stream to ktable join

Question

I am trying to join a

• KStream: created from a topic, the topic has JSON value. I re-key the stream using two attributed from the value. example value (snippet of the json). I created a custom pojo class and use a custom serdes. {"value":"0","time":1.540753118800291E9,,"deviceIp":"111.111.111.111","deviceName":"KYZ1","indicatorName":"ifHCInOctets"}

keys are mapped as:

map((key, value) -> KeyValue.pair(value.deviceName+value.indicatorName, value))

I do a peek on the KStream and prints both key and the attributes I used. Looks all good.

• KTable: I create a ktable from a topic, I am writing to the topic using a python script and the key for the topic is KYZ1ifHCInOctets , the combination of device name and indicator name (from above). I do a toStream and then a peek on the resulting stream. Keys and values all seems fine.

Now when i do a inner join and do a peek or through/to a topic i see the key and values are mismatched. Join doesn't seems to work,

  KStream<String, MyPojoClass> joined= datastream.join(table, 
          (data,table)->data
          ,Joined.with(Serdes.String(),myCustomSerde,Serdes.String())
          );

key = XYZ1s1_TotalDiscards
Value = {"deviceName":"ABC2", "indicatorName":"jnxCosQstatTxedBytes"}

I have the exactly the same thing working through ksql, but wanted to do my own stream app.

Answer 1

现在，对于错误的根源听起来如此愚蠢，我的PoJo类几乎没有什么静态的属性:-(，导致了错误的键。