Spring Boot and Spring Batch: Creating a Job Runner for Database Exports

Spring Boot, along with Spring Batch, provides an excellent foundation for writing batch jobs in Java. In this post, we’ll walk through creating a job runner that initiates a process to export a CSV file of Books from a database, all triggered by an HTTP POST request. We’ll also build a mechanism to retrieve a list of jobs and the resulting files.

Prerequisites

To follow this guide, you should have a basic understanding of Spring Boot and familiarity with Spring Batch. You’ll also need a Spring Boot project set up and connected to a database.

Defining Our Spring Batch Job

Let’s start by defining our job. We’ll create a simple job that reads from a database, processes the data, and writes it to a CSV file.

Reader

The reader is responsible for reading data from the database. We’ll use JdbcCursorItemReader for this purpose ##language-java

`@Bean
public JdbcCursorItemReader reader(DataSource dataSource) {
JdbcCursorItemReader reader = new JdbcCursorItemReader();
reader.setDataSource(dataSource);
reader.setSql(SELECT id, title, author FROM book);
reader.setRowMapper(new BeanPropertyRowMapper<>(Book.class));
return reader;
}`

## **Processor** The processor will perform transformations on our data. For this example, we won't be performing any transformations, so our processor is a simple pass-through. ##language-java

‍`@Bean
public ItemProcessor processor() {
return (book) -> book;
}`

## **Writer** The writer is responsible for writing our processed data to a CSV file. ##language-java

@Bean
public FlatFileItemWriter writer() {
FlatFileItemWriter writer = new FlatFileItemWriter<>();
writer.setResource(new FileSystemResource(books.csv));
writer.setLineAggregator(new DelimitedLineAggregator() {{
setDelimiter(

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