produce-generic-records-consume-avro-messages.md

Java Producer using generic schema and Consumer using Avro schema

This example demonstrates how to produce messages to Apache Pulsar using generic schema, and how to consume messages from Apache Pulsar using Avro schema.

Prerequisites

• Java 1.8 or higher to run the demo application
• Maven to compile the demo application
• Pulsar 2.3.0 or higher

Examples

• Java Generic Schema Producer
• Java Avro Consumer

Steps

1. Start Pulsar standalone. You can follow the detailed instructions in Pulsar documentation to start a Pulsar standalone locally.

   bin/pulsar standalone

2. Clone the examples repo and build the schema examples.

   git clone https://github.com/streamnative/pulsar-examples.git

   cd pulsar-examples/clients

   mvn -am -pl schema clean package

3. Run the Generic schema producer example to produce 10 generic records to a pulsar topic avro-payments.

   java -cp schema/target/pulsar-schema-examples.jar io.streamnative.examples.schema.generic.GenericSchemaProducerExample

   After running this producer example, you will see the following successful message.

   Successfully produced 10 messages to a topic called avro-payments

4. Run the Avro consumer example to receive the produced generic records from topic avro-payments.

   java -cp schema/target/pulsar-schema-examples.jar io.streamnative.examples.schema.avro.AvroSchemaConsumerExample

   After running this consumer example, you will see the following output.

   key = id-0, value = {"id": "id-0", "amount": 0.0}
   key = id-1, value = {"id": "id-1", "amount": 1000.0}
   key = id-2, value = {"id": "id-2", "amount": 2000.0}
   key = id-3, value = {"id": "id-3", "amount": 3000.0}
   key = id-4, value = {"id": "id-4", "amount": 4000.0}
   key = id-5, value = {"id": "id-5", "amount": 5000.0}
   key = id-6, value = {"id": "id-6", "amount": 6000.0}
   key = id-7, value = {"id": "id-7", "amount": 7000.0}
   key = id-8, value = {"id": "id-8", "amount": 8000.0}
   key = id-9, value = {"id": "id-9", "amount": 9000.0}

   Then you can press "Ctrl+C" to stop the consumer example.