Quick demo to use Reactive Streams Ingestion (RSI) Library as an ItemWriter in Spring Batch
The use case for this demo is a simple Extract-Transform-Load (ETL) process that reads records from a csv file, executes a simple transformation and then loads the transformed records into an Oracle Database using the RSI Library.
In this demo we create a simple job with only one step. As depicted in the picture the step will use a an ItemReader, process the record and then persist it using an ItemWriter. The configuration of the job can be visualized in BatchConfiguration.java.
The ItemReader (Extract Phase) is an out-of-the-box FlatFileItemReader provided by Spring Batch. It reads records from customer.csv and maps each line to a Customer.java record (a simple POJO).
The ItemProcessor (Transform Phase) implemented in CustomerItemProcessor.java is for educational purposes. It maps a Customer into a new Customer (it could have been mapped into a complete different entity) upper-casing the values.
The ItemWriter (Load Phase) is where we integrate the Reactive Streams Ingestion (RSI) Library. The RSIItemWriter.java class implements the ItemWriter interface allowing to be hooked into the job. Overriding the 'write' method the class uses RSI to stream records into the database. The Customer class has the annotations to map the fields into the columns of the target database.
To execute this demo you just have to:
- Create the metadata used by Spring Batch defined in metadata.sql.
- Define the location of the metadata in application.properties.
- create the table in the target database defined in the Customer class.
- Define the location of the target database in BatchConfiguration.java (in the ItemWriter).
- Build the demo with maven clean install.
- Execute it with java -jar target/demo-spring-batch-0.0.1-SNAPSHOT.jar.