Spring Batch: Specify multiple steps using from, on and to functions

Using ‘from’, ‘on’ and ‘to’ functions we can specify multiple steps and their flow of execution.

 

 

‘from’ method takes a step as argument and start the flow from this step.

 

‘on’ method takes a string as argument and branch into a flow conditional on the outcome of the current step.

 

‘to’ method used specify next step.

 

Example

@Bean
public Job job() {
	return this.jobBuilderFactory.get("My-Job").start(step1()).on("COMPLETED").to(step2()).from(step2())
			.on("COMPLETED").to(step3()).from(step3()).end().build();
}

Find the below working application.

 

Step 1: Create new maven project ‘job-with-multiple-steps-from-on-to’.

 

Step 2: Update pom.xml with maven dependencies.

 

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<groupId>com.sample.app</groupId>
	<artifactId>job-with-multiple-steps-from-on-to</artifactId>
	<version>1</version>

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>2.1.6.RELEASE</version>
	</parent>

	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
	</properties>

	<dependencies>

		<!-- https://mvnrepository.com/artifact/org.springframework.batch/spring-batch-core -->
		<dependency>
			<groupId>org.springframework.batch</groupId>
			<artifactId>spring-batch-core</artifactId>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-data-jpa</artifactId>
		</dependency>

		<dependency>
			<groupId>com.h2database</groupId>
			<artifactId>h2</artifactId>
		</dependency>
	</dependencies>
</project>

Step 3: Create a package ‘com.sample.app.configuration’ and define JobConfiguration.

 

JobConfiguration.java

package com.sample.app.configuration;

import org.springframework.batch.core.Job;
import org.springframework.batch.core.Step;
import org.springframework.batch.core.StepContribution;
import org.springframework.batch.core.configuration.annotation.EnableBatchProcessing;
import org.springframework.batch.core.configuration.annotation.JobBuilderFactory;
import org.springframework.batch.core.configuration.annotation.StepBuilderFactory;
import org.springframework.batch.core.scope.context.ChunkContext;
import org.springframework.batch.repeat.RepeatStatus;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
@EnableBatchProcessing
public class JobConfiguration {
	@Autowired
	private JobBuilderFactory jobBuilderFactory;

	@Autowired
	private StepBuilderFactory stepBuilderFactory;

	@Bean
	public Step step1() {
		return this.stepBuilderFactory.get("My-Step1")
				.tasklet((StepContribution contribution, ChunkContext chunkContext) -> {
					System.out.println("Step1:  Finished Execution");

					return RepeatStatus.FINISHED;

				}).build();
	}

	@Bean
	public Step step2() {
		return this.stepBuilderFactory.get("My-Step2")
				.tasklet((StepContribution contribution, ChunkContext chunkContext) -> {
					System.out.println("Step2:  Finished Execution");

					return RepeatStatus.FINISHED;

				}).build();
	}

	@Bean
	public Step step3() {
		return this.stepBuilderFactory.get("My-Step3")
				.tasklet((StepContribution contribution, ChunkContext chunkContext) -> {
					System.out.println("Step3:  Finished Execution");

					return RepeatStatus.FINISHED;

				}).build();
	}

	@Bean
	public Job job() {
		return this.jobBuilderFactory.get("My-Job").start(step1()).on("COMPLETED").to(step2()).from(step2())
				.on("COMPLETED").to(step3()).from(step3()).end().build();
	}

}

Step 4: Define App.java.

 

App.java

package com.sample.app;

import org.springframework.batch.core.configuration.annotation.EnableBatchProcessing;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@EnableBatchProcessing
@SpringBootApplication
public class App {

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

Step 5: Create application.properties file under src/main/resources folder.

 

application.properties

logging.level.root=INFO
logging.level.org.hibernate=ERROR

## H2 specific properties
spring.h2.console.enabled=true
spring.h2.console.path=/h2

spring.datasource.url=jdbc:h2:file:~/db/myOrg.db;DB_CLOSE_ON_EXIT=FALSE;DB_CLOSE_DELAY=-1;

spring.datasource.username=krishna
spring.datasource.password=password123

spring.datasource.driverClassName=org.h2.Driver

## JPA specific properties
# Creates the schema, destroying previous data.
spring.jpa.hibernate.ddl-auto=create

spring.jpa.database-platform=org.hibernate.dialect.H2Dialect

spring.jpa.show-sql=false
spring.jpa.properties.hibernate.format_sql=false

## Database connection pooling properties
# Number of ms to wait before throwing an exception if no connection is available.
spring.datasource.max-wait=10000

# Maximum number of active connections that can be allocated from this pool at the same time.
spring.datasource.tomcat.max-active=10
spring.datasource.tomcat.max-idle=5
spring.datasource.tomcat.min-idle=3

Total project structure looks like below.

Run ‘App.java’, you will see below messages in console.

2020-03-30 14:35:23.919  INFO 21494 --- [           main] o.s.b.c.l.support.SimpleJobLauncher      : Job: [FlowJob: [name=My-Job]] launched with the following parameters: [{}]
2020-03-30 14:35:23.941  INFO 21494 --- [           main] o.s.batch.core.job.SimpleStepHandler     : Executing step: [My-Step1]
Step1:  Finished Execution
2020-03-30 14:35:23.967  INFO 21494 --- [           main] o.s.batch.core.job.SimpleStepHandler     : Executing step: [My-Step2]
Step2:  Finished Execution
2020-03-30 14:35:23.981  INFO 21494 --- [           main] o.s.batch.core.job.SimpleStepHandler     : Executing step: [My-Step3]
Step3:  Finished Execution
2020-03-30 14:35:23.990  INFO 21494 --- [           main] o.s.b.c.l.support.SimpleJobLauncher      : Job: [FlowJob: [name=My-Job]] completed with the following parameters: [{}] and the following status: [COMPLETED]

You can download complete working application from this link.

https://github.com/harikrishna553/springboot/tree/master/batch/job-with-multiple-steps-from-on-to

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