Hi Adrienne, How do you enter the input on t1 topic? If using kafka-console-producer, you'll need to pass in keys as well as values. Here is an example: http://www.shayne.me/blog/2015/2015-06-25-everything-about-kafka-part-2/ <http://www.shayne.me/blog/2015/2015-06-25-everything-about-kafka-part-2/>
Thanks Eno > On 15 Jun 2016, at 17:21, Adrienne Kole <[email protected]> wrote: > > Hi community, > > Probably it is very basic question, as I am new to Kafka Streams. > I am trying to initialize KTable or KStream from kafka topic. However, I > don't know how to avoid getting null keys. So, > > KTable<String, String> source = > builder.stream(Serdes.String(),Serdes.String(),"t1"); > source.print(); > > I enter the input on t1 topic as: > > one > two > one one > > and get as a result: > > null, (one <-null) > null, (two <-null) > null, (one one <-null) > > > So, the key is always null. > > Is the key supposed to initialize after getting input from topic? If yes, > how can I initialize key in KTable after getting input? For example in > KStream we have KeyValueMapper that can be used to assign new keys and > values. However, in KTable we have only ValueMappers. > > If not, how can I initialize the key of KTable from the input from given > topic? > > > Cheers > Adrienne
