Here are some tips, including the required configurations and code samples, to help you implement a Kafka consumer in Java.
Required dependencies
Ensure that you have the following dependencies in your project:
<dependency>
<groupId>org.springframework.kafka</groupId>
<artifactId>spring-kafka</artifactId>
</dependency>
<dependency>
<groupId>io.strimzi</groupId>
<artifactId>kafka-oauth-client</artifactId>
<version>0.6.1</version>
</dependency>
<dependency>
<groupId>org.apache.kafka</groupId>
<artifactId>kafka-clients</artifactId>
<version>2.5.1</version>
</dependency>
<dependency>
<groupId>io.opentracing.contrib</groupId>
<artifactId>opentracing-kafka-client</artifactId>
<version>0.1.13</version>
</dependency>
Configuration
Ensure that you have the following configuration in your application.yml or application.properties file:
spring.kafka:
bootstrap-servers: URL_OF_THE_KAFKA_SERVER
consumer:
group-id: ADD_CONSUMER_NAME
auto-offset-reset: earliest
key-deserializer: org.apache.kafka.common.serialization.StringDeserializer
value-deserializer: org.apache.kafka.common.serialization.StringDeserializer
properties:
interceptor:
classes: io.opentracing.contrib.kafka.TracingConsumerInterceptor
security.protocol: "SASL_PLAINTEXT"
sasl.mechanism: "OAUTHBEARER"
sasl.jaas.config: "org.apache.kafka.common.security.oauthbearer.OAuthBearerLoginModule required ;"
sasl.login.callback.handler.class: io.strimzi.kafka.oauth.client.JaasClientOauthLoginCallbackHandler
kafka:
consumerThreads: 1
authorizationExceptionRetryInterval: 10
ADD_NEEDED_TOPIC_NAMES_HERE
Code sample for a Kafka Listener
Here’s an example of a Kafka listener method:
@KafkaListener(topics = "TOPIC_NAME_HERE")
public void listen(ConsumerRecord<String, String> record) throws JsonProcessingException {
SomeDTO request = objectMapper.readValue(record.value(), SomeDTO.class);
}
Make sure to replace “TOPIC_NAME_HERE” with the actual name of the Kafka topic you want to consume from. Additionally, ensure that you have the necessary serialization and deserialization logic based on your specific use case.
