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>
Download Source Code
Download it – SpringBatch-Tasklet-Example.zip (13 KB)
Hi Mykong and other participants in the discussion.
Can someone help me to find some solution for my issue.
I have a tasklet which is calling another service,
@Override
public RepeatStatus execute(StepContribution contribution, ChunkContext chunkContext) throws Exception {
try {
Map map = chunkContext.getStepContext().getJobParameters();
String number = String.valueOf(map.get(“number”));// 10
numberGenerator.generateNumbers(Integer.parseInt(number));// print numbers 123…10
} catch (Exception e) {
e.printStackTrace();
return RepeatStatus.CONTINUABLE;
}
return RepeatStatus.FINISHED;
}
When I call jobOperator.stop(executionID), then updating execution status as stopping in database but excution is not getting stopped aftr 1 hour aslo.
Hello Mkyong,
is there any documentation on the way to write a batch “spring batch” that can read data from various sources like, csv, xml, txt files and REST API, according to source detection type, than write the data to one destination repository ?
Hello Mkyong – Please develop a code to read data from mongoDB and write to XML file? Looking to get response on this.
What libraries are you using? i have a library error
Error creating bean with name ‘step1’: Initialization of bean failed; nested exception is java.lang.reflect.MalformedParameterizedTypeException
I am facing same error as mentioned in the link –
(http://stackoverflow.com/questions/29478082/java-lang-illegalstateexception-assertion-failed-this-state-invariant-must)
Could you please guide?
Error for your reference:-
java.lang.IllegalStateException: [Assertion failed] – this state invariant must be true
char [] charArr; // need to be initialize
int [] lens = new int[charArr.length];
public static longestPanlidrom(int rightMost, int currentMid, int length) {
if(currentMid + length > rightMost) {
rightMost++;
if(charArr[currentMid – length] = charArr[rightMost])
length++;
} else {
if(charArr[currentMid – length] == char[currentMid + length]
}
}
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