Spring batch – Quick start

TODO: Batch process introduction

TODO: Spring batch architecture introduction

Project Initialization

Spring batch can be initialized with Spring intializr.

<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-batch</artifactId>
</dependency>
<dependency>
	<groupId>org.springframework.batch</groupId>
	<artifactId>spring-batch-test</artifactId>
	<scope>test</scope>
</dependency>

One of the essential dependencies of spring batch is Spring data-jpa, as it needs to store and maintain the metadata information of the Job and step execution history.

<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
	<groupId>com.h2database</groupId>
	<artifactId>h2</artifactId>
	<scope>runtime</scope>
</dependency>

The main SpringBootApplication class may look similar as shown below. Run it and ensure that the context is loading properly without any issues.

package com.kesavan.springbatchexp;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class SpringbatchexpApplication {
	public static void main(String[] args) {
	      SpringApplication.run(SpringbatchexpApplication.class, args);
	}
}

Step-1 : Adding a scheduler to the application.

For our understanding purpose, let us use a Scheduler to launch the jobs. In this step, let’s just introduce a scheduler that runs every second.

The following annotations can be used to configure a scheduler.

1. @EnableScheduling – to your SpringBootApplication class
2. @Scheduled – to the method in your scheduler class
   • A scheduler class needs to be created – Annotated with @Component annotation

package com.kesavan.springbatchexp.job;

import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;

@Component
public class DataSummarizerJobScheduler {

    @Scheduled(fixedRate = 1000)
    public void launchJob() {
        System.out.println("Scheduler runs now : "+System.currentTimeMillis());
    }
}