Spring & SpringBatch EN

Spring & Batch
October 2017
M. Mohamed

2Copyright © 2017 Capgemini. All rights reserved
CSD | October 2017
Plan & Goals
Plan
1. A tour of Spring & Spring-Boot
2. What is a Batch and Spring-Batch ?
3. How does it work ?
4. Advanced notions and applications
5. A good example
Goals
1. Understanding how Spring-Batch works
2. Detecting use cases
3. Be able to do Batch and go even further with ...

Hello « Spring Framework »…

CSD | October 2017
Spring Framework (Core 1/3)
Open-source Java framework created in 2003 by “Pivotal Software”
A light container (unlike EJBs)
Mainly based on injection of dependency and AOP
Easy integration of other Framework (Hibernate, JSF, Thymeleaf, ...)

CSD | October 2017
Spring Framework (Boot 2/3)
Little configuration (self configurable as long as possible)
Runnable Application, autonomous even in production.
Embedded Tomcat (+ Jetty) , no need War
No need for XML files (context.xml, web.xml, …) @annotations

CSD | October 2017
Spring Framework (Trend 3/3 @GoogleTrend)

CSD | October 2017
Batch (What's this ? 1/2)
Lot Data Processing
Large data process
Several operations ensue for each lot
Automatic or manual triggering

CSD | October 2017
Batch (Example 2/2)
Example : import of daily orders
Reading a lot of
commands from
a file
Checking
orders
Saving the lot of
commands in
storage system
Repeat this cycle for each lot of orders until the last
Triggered by CRON, everyday at 5 am, before the arrival of the collaborators

CSD | October 2017
Spring-Batch (and ! 1/6)
Open-source framework for Batch Processing
Robust Batch Application (Entreprise application)
Reusable functions for data processing
Adds a standard approach to defining Batch Jobs

CSD | October 2017
Spring-Batch (More 2/6)
Transaction management (Commit interval & Rollback)
Batch processing easily (Chuncked process)
Error Management, Recovery and Stopping Jobs
All in Spring…

CSD | October 2017
Spring-Batch (Concept 3/6)
A Job is defined by a Step Flow (one or more)
A Step usually defined as a Reader, Processor and Writer
A Step can also define a simple Tasklet
A Job Repository (JobRepository) and a Job Executor (JobLauncher)
Origin : Spring.io

CSD | October 2017
Spring-Batch (How does it work ? 4/6)
The Reader read one item at a time
The Processor processe one item at a time
When the lot is read and processed, the Writer writes it
Origin : Spring.io

CSD | October 2017
Spring-Batch (Advanced 5/6)
Flow of Sequential, Conditional or Parallel Step
Split Flow and Multi-threading
Many Listeners (StepExecutionListener, ChunkListener, ...)
Exceptions management

CSD | October 2017
Spring-Batch (Diagramme 6/6)
Origin : Cépria FR

CSD | October 2017
Example
from life…

CSD | October 2017
Example of use (Context 1/8)
Web application that can use Jobs from View
Track Jobs Status
Allow to play Jobs in Synchronous and Asynchronous
Three Jobs, one for importing CSV files to Database, one for exporting
data to a JSON file, and one Job for importing and exporting large
amounts of data (200,000 lines) into less than 10 minutes

CSD | October 2017
Example of use (Business request 2/8)
Import Job :
• Input : a CSV file containing employee information and their annual gross
salaries
• Output : processed information and taxes calculated and saved in the
database
Export Job :
• Input : employee information and taxes calculated and saved in the
database
• Output : A JSON file containing all data
+ A REST API to perform tax calculation and validation

CSD | October 2017
Example of use (Architecture & technical choices 3/8)
Use of Spring-Boot with Spring-MVC and Srping-Batch
Integration of Thymeleaf as a templating engine (+ nekohtml)
MySQL Driver, Mokito for tests and Jackson for JSON support
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
…
<artifactId>spring-boot-starter-batch</artifactId>
…
<artifactId>spring-boot-starter-data-jpa</artifactId>
…
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
…
<artifactId>spring-boot-starter-thymeleaf</artifactId>
…
<groupId>net.sourceforge.nekohtml</groupId>
<artifactId>nekohtml</artifactId>
…
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>

CSD | October 2017
Example of use (Solution diagramme 4/8)

CSD | October 2017
Example of use (Programming 5/8)
An interface is available to define a Tasklet
public interface ItemReader<T> {
T read() throws Exception, UnexpectedInputException , ParseException;
}
public interface ItemWriter<T> {
void write(List<? extends T> items) throws Exception;
}
public interface ItemProcessor<I, O> {
O process(I item) throws Exception;
}
Three interfaces are available to define a Reader, Processor and Writer
public interface Tasklet {
RepeatStatus execute(StepContribution contribution, ChunkContext chunkContext) throws Exception
}
An interface is available to define a Partitioner
public interface Partitioner {
Map<String, ExecutionContext> partition(int gridSize);
}

CSD | October 2017
Example of use (Annotation job 6/8)
@Bean
public ItemReader<Person> reader() {
return new PersonReaderFromFile();
}
@Bean
public ImportPersonItemProcessor processor() {
return new ImportPersonItemProcessor();
}
@Bean
public ItemWriter<Person> writer() {
return new PersonWriterToDataBase();
}
@Bean
public Tasklet cleaner() {
return new CleanDBTasklet ();
}
@Bean
public Job importUserJob() {
return jobBuilderFactory.get("importUserJob").incrementer(new RunIdIncrementer()).flow(stepClean())
.next(stepImport()).end().listener(new ImportJobExecutionListener(reader())
.validator(new FileNameParameterValidator()).build();
}
@Bean
public Step stepImport() {
return stepBuilderFactory.get("stepImport").<Person, Person>chunk(10).reader(reader()).processor(processor()).writer(writer()).build();
}
@Bean
public Step stepClean() {
return stepBuilderFactory.get("stepClean").tasklet(cleaner()).build();
}

CSD | October 2017
Example of use (XML Jobs 7/8)
<batch:job id="importUserJob">
<batch:step id="stepClean" next="importStep">
<batch:tasklet ref="cleanDBTasklet" />
</batch:step>
<batch:step id="importStep">
<batch:tasklet>
<batch:chunk reader="reader" writer="writer" processor="processor" commit-interval="10" />
</batch:tasklet>
</batch:step>
</batch:job>
<bean id="reader" class="com.capgemini.reader.PersonReaderFromFile" scope="step" />
<bean id="processor" class="com.capgemini.processor.ImportPersonItemProcessor" scope="step" />
<bean id="writer" class="com.capgemini.writer.PersonWriterToDataBase" scope="step" />
<bean id="cleanDBTasklet" class="com.capgemini.tasklet.CleanDBTasklet" />
<batch:job id=“exportUserJob">
<batch:step id=“exportStep">
<batch:tasklet>
<batch:chunk reader="reader" writer="writer" processor="processor" commit-interval="10" />
</batch:tasklet>
</batch:step>
</batch:job>
<bean id="reader" class="com.capgemini.reader.PersonReaderFromDataBase" scope="step" />
<bean id="processor" class="com.capgemini.processor.ExportPersonItemProcessor" scope="step" />
<bean id="writer" class="com.capgemini.writer.PersonWriterToFile" scope="step" />

CSD | October 2017
Example of use (Application 8/8)

CSD | October 2017
Demo (Result and Conclusion1/6)
Small or medium file import:
• For small files, an average of 4 seconds for Synchronous and
Asynchronous modes
• For medium-sized files (10,000 lines), an average of 43 seconds of
processing between Synchronous and Asynchronous
Import large file: A processing average of 13 minutes
Export 1000 rows or 10,000 rows : For the 1000 rows, an average of 4
seconds of processing, and for the 100,000 rows, an average of 30
seconds
Export of 200,000 rows : A processing average of 12 minutes
=> For an import and export of 200,000 lines, it exceeds 10 minutes

CSD | October 2017
Demo (Solution 2/6)
To import and export 200,000 lines in less than 10 minutes, multi-threading
is one of the solutions
Multi-threading: multiple Threads, perform a parallel task
New problem: the FileReader and FileWriter are not ThreadSafe
Solution for the FileReader: Split the input file so that each file is processed
by a Thread
Solution for the FileWriter: paginate data from the database to export
several files and concatenate them at the end of the Process

CSD | October 2017
Demo (Configuration 3/6)
<batch:job id="transformJob">
<batch:step id="deleteDir" next="cleanDB">
<batch:tasklet ref="fileDeletingTasklet" />
</batch:step>
<batch:step id="cleanDB" next="countThread">
<batch:tasklet ref="cleanDBTasklet" />
</batch:step>
<batch:step id="countThread" next="split">
<batch:tasklet ref="countThreadTasklet" />
</batch:step>
<batch:step id="split" next="partitionerMasterImporter">
<batch:tasklet>
<batch:chunk reader="largeCSVReader" writer="smallCSVWriter"
commit-interval="#{jobExecutionContext['chunk.count']}" />
</batch:tasklet>
</batch:step>
<batch:step id="partitionerMasterImporter" next="partitionerMasterExporter">
<partition step="importChunked" partitioner="filePartitioner">
<handler grid-size="10" task-executor="taskExecutor" />
</partition>
</batch:step>
<batch:step id="partitionerMasterExporter" next="concat">
<partition step="exportChunked" partitioner="dbPartitioner">
<handler grid-size="10" task-executor="taskExecutor" />
</partition>
</batch:step>
<batch:step id="concat">
<batch:tasklet ref="concatFileTasklet" />
</batch:step>
</batch:job>

CSD | October 2017
<batch:step id="importChunked">
<batch:tasklet>
<batch:chunk reader="smallCSVFileReader" writer="dbWriter"
processor="importProcessor" commit-interval="500">
</batch:chunk>
</batch:tasklet>
</batch:step>
<batch:step id="exportChunked">
<batch:tasklet>
<batch:chunk reader="dbReader" writer="jsonFileWriter" processor="exportProcessor" commit-
interval="#{jobExecutionContext['chunk.count']}">
</batch:chunk>
</batch:tasklet>
</batch:step>
<bean id="jsonFileWriter" class="com.capgemini.writer.PersonWriterToFile" scope="step">
<property name="outputPath" value="csv/chunked/paged-#{stepExecutionContext[page]}.json" />
</bean>
<bean id="dbReader" class="com.capgemini.reader.PersonReaderFromDataBase" scope="step">
<property name="iPersonRepository" ref="IPersonRepository" />
<property name="page" value="#{stepExecutionContext[page]}"/>
<property name="size" value="#{stepExecutionContext[size]}"/>
</bean>
<bean id="countThreadTasklet" class="com.capgemini.tasklet.CountingTasklet" scope="step">
<property name="input" value="file:csv/input/#{jobParameters[filename]}" />
</bean>
<bean id="cleanDBTasklet" class="com.capgemini.tasklet.CleanDBTasklet" />
<bean id="fileDeletingTasklet" class="com.capgemini.tasklet.FileDeletingTasklet">
<property name="directory" value="file:csv/chunked/" />
</bean>

CSD | October 2017
<bean id="concatFileTasklet" class="com.capgemini.tasklet.FileConcatTasklet">
<property name="directory" value="file:csv/chunked/" />
<property name="outputFilename" value="csv/output/export.json" />
</bean>
<bean id="filePartitioner" class="com.capgemini.partitioner.FilePartitioner">
<property name="outputPath" value="csv/chunked/" />
</bean>
<bean id="dbPartitioner" class="com.capgemini.partitioner.DBPartitioner" scope="step">
<property name="pageSize" value="#{jobExecutionContext['chunk.count']}" />
</bean>
<bean id="largeCSVReader" class="com.capgemini.reader.LineReaderFromFile" scope="step">
<property name="inputPath" value="csv/input/#{jobParameters[filename]}" />
</bean>
<bean id="smallCSVWriter" class="com.capgemini.writer.LineWriterToFile" scope="step">
<property name="outputPath" value="csv/chunked/"></property>
</bean>
<bean id="smallCSVFileReader" class="com.capgemini.reader.PersonReaderFromFile" scope="step">
<constructor-arg value="csv/chunked/#{stepExecutionContext[file]}" />
</bean>
<bean id="importProcessor" class="com.capgemini.processor.ImportPersonItemProcessor" />
<bean id="exportProcessor" class="com.capgemini.processor.ExportPersonItemProcessor" />
<bean id="dbWriter" class="com.capgemini.writer.PersonWriterToDataBase">
<property name="iPersonRepository" ref="IPersonRepository" />
</bean>

CSD | October 2017
The test
With multi-threading

CSD | October 2017
Test (Result1/3)

CSD | October 2017
Test (Threads 2/3)
Before Job aunch
During the
execution of the
Job

CSD | October 2017
Test (Output 3/3)

CSD | October 2017
Summary

CSD | October 2017
Summary (Good + 1/2)
Define a pattern for Batch
Embed Batch in any kind of Spring application easily
Reliability, maintainability
Advanced functions such as "Multi-Threading"
Integrated batch testing
Error Tolerance and Recovery

CSD | October 2017
Summary (Not good – 2/2)
The Spring Batch Admin project is no longer maintained : mandatory switch
to the Spring Cloud Data Flow
Difficulty to run a job defined by annotation in a project under JAR package
embarking several Jobs
Version compatibility issues between Spring Batch and H2 Database, very
useful for testing Jobs

CSD | October 2017
Useful links

CSD | October 2017
Useful links
Full source code of the project : https://gitlab.com/mmohamed/spring-batch
Documentation :
• http://projects.spring.io/spring-batch/#quick-start
• https://blog.octo.com/spring-batch-par-quel-bout-le-prendre
• https://blog.netapsys.fr/spring-batch-par-lexemple-2
• http://jeremy-jeanne.developpez.com/tutoriels/spring/spring-batch/

www.capgemini.com
The information contained in this presentation is proprietary.
© 2017 Capgemini. All rights reserved. Rightshore® is a trademark belonging to Capgemini.
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