Spring Batch Tasklet example（二）

In Spring batch, the Tasklet is an interface, which will be called to perform a single task only, like clean or set up resources before or after any step execution. In this example, we will show you how to use Tasklet to clean up the resource (folders) after a batch job is completed.

P.S The FileDeletingTasklet example below is taken from the Spring Batch samples project.

1. Tasklet Example

A Java class to implement Tasklet interface, and delete all the files in the given directory.

FileDeletingTasklet.java

package com.mkyong.tasklet;

import java.io.File;

import org.springframework.batch.core.StepContribution;
import org.springframework.batch.core.UnexpectedJobExecutionException;
import org.springframework.batch.core.scope.context.ChunkContext;
import org.springframework.batch.core.step.tasklet.Tasklet;
import org.springframework.batch.repeat.RepeatStatus;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.core.io.Resource;
import org.springframework.util.Assert;

public class FileDeletingTasklet implements Tasklet, InitializingBean {

  private Resource directory;

  @Override
  public void afterPropertiesSet() throws Exception {
	Assert.notNull(directory, "directory must be set");
  }

  @Override
  public RepeatStatus execute(StepContribution contribution, 
               ChunkContext chunkContext) throws Exception {

	File dir = directory.getFile();
	Assert.state(dir.isDirectory());

	File[] files = dir.listFiles();
	for (int i = 0; i < files.length; i++) {
	  boolean deleted = files[i].delete();
	  if (!deleted) {
		throw new UnexpectedJobExecutionException(
                       "Could not delete file " + files[i].getPath());
	  } else {
	        System.out.println(files[i].getPath() + " is deleted!");
	  }
	}
	return RepeatStatus.FINISHED;
  }

  public Resource getDirectory() {
	return directory;
  }

  public void setDirectory(Resource directory) {
	this.directory = directory;
  }

}

2. Batch Jobs

A batch job to perform following steps :

Step 1 - To read multiple files from csv/inputs/, and write it to somewhere.
Step 2 - After step 1 is completed, run fileDeletingTasklet to delete all the files from directory csv/inputs/.

spring-batch-job.xml

  <job id="readMultiFileJob" xmlns="http://www.springframework.org/schema/batch">
	<step id="step1" next="deleteDir">
	  <tasklet>
		<chunk reader="multiResourceReader" writer="flatFileItemWriter" commit-interval="1" />
	  </tasklet>
	</step>
	<step id="deleteDir">
		<tasklet ref="fileDeletingTasklet" />
	</step>
  </job>
	
  <bean id="fileDeletingTasklet" class="com.mkyong.tasklet.FileDeletingTasklet" >
	<property name="directory" value="file:csv/inputs/" />
  </bean>
	
  <bean id="multiResourceReader" class=" org.springframework.batch.item.file.MultiResourceItemReader">
	<property name="resources" value="file:csv/inputs/domain-*.csv" />
	<property name="delegate" ref="flatFileItemReader" />
  </bean>