Kafka Streams Hello World

Now that we have some knowledge about Kafka Streams, let’s build our first Kafka Streams application! In line with software development tradition, we’ll build a Hello World application. First, let’s define the requirements.

Application requirements

• The application will consume records from a Kafka topic called names.

• Each record will be a simple String.

• The application will print each record it consumes.

• Blank values will be ignored.

• Each name will be prepended with "Hello, ".

• Each transformed record will be printed.

• Each transformed record will be sent to an output Kafka topic called greetings.

Topology

It is a good practice to design the topology before writing it. We can draw our topology as a graph: