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>