Kafka输出流

Question

I've been working with the kafka consumer- and producer api for a while now and want to try my hand at the streams api. I've looked at a ton of references online but I cant figure out this one simple thing.

How do you make a KStream that only sends messages to an output topic.

Take for instance this most basic example they have on the github repo: https://github.com/confluentinc/examples/blob/3.2.x/kafka-streams/src/main/java/io/confluent/examples/streams/WordCountLambdaExample.java It takes messages from one queue and posts them to a different one after manipulating it.

Something like this:

final KStreamBuilder builder = new KStreamBuilder();
final KStream<String, String> textLines = builder.stream();
// do the dirty work...
textLines.to("outputTopic") 

But builder.stream(); does not exists it needs at the very least a input topic name.

Should I just stick to a regular kafka producer for this? If so I have had no luck finding a resource that says this explicitly.

Answer 1

Kafka Streams API is designed to consume topics as input streams, process the records, and write the results back to topics. It's not designed to just write data to Kafka.

So yes, you should use KafkaProducer if you want to write data to a topic.