application-kafka.properties

spring.kafka.consumer.auto-offset-reset=earliest
spring.kafka.consumer.enable-auto-commit=true
spring.kafka.consumer.max-poll-records=100
spring.kafka.consumer.fetch-max-wait=2s
spring.kafka.listener.type=BATCH
spring.kafka.listener.concurrency=12
spring.kafka.consumer.group-id=batchTest1
spring.kafka.client-id=batchTest1
spring.kafka.listener.ack-mode=BATCH