spring-cellular

Batch application that generates billing reports

Run the application

Open the terminal

$ ./mvnw clean package -Dmaven.test.skip=true

Then, launch the job and pass the input file as a parameter with the following command:

$ java -jar target/billing-job-0.0.1-SNAPSHOT.jar 
input.file=src/main/resources/billing-2023-01.csv

$ docker exec postgres psql -U postgres -c 'select * from BATCH_STEP_EXECUTION;'

Run the tests

$ ./mvnw clean test -Dspring.batch.job.enabled=false

Review database structure

$ docker exec postgres psql -U postgres -c 'select count(*) from BILLING_DATA;'

The property -Dspring.batch.job.enabled=false disables the automatic execution of the job by Spring Boot. Without this property, the job will be executed twice: a first time at the application's startup, and a second time during the test. This is obviously not desired when running tests, hence the use of that property.

Reading and Writing Data

Understanding the Chunk-Oriented Processing Model

Spring Batch comes with a processing model that is designed and implemented to address those challenges. It is called the chunk-oriented processing model. The idea of this model is to process the datasource in chunks of a configurable size.