Spring-Batch Tutorial

Guide for Application Developers

Agenda “Hello world!” job Simple job – programming a Tasklet

directly Common job – weaving standard

components Sample jobs

“Hello World!” - taskletpublic class HelloWorldTasklet implements Tasklet {

public ExitStatus execute() throws Exception {

System.out.println("Hello world!");

return ExitStatus.FINISHED;

}

}

“Hello World!” - taskletpublic class HelloWorldTasklet implements Tasklet {

public ExitStatus execute() throws Exception {

System.out.println("Hello world!");

return ExitStatus.FINISHED;

}

}

“Hello World!” - configuration<bean id="jobConfiguration" parent="simpleJob">

<property name="name" value="helloWorldJob" />

<property name="steps">

<list>

<bean id="step1" parent="simpleStep">

<constructor-arg>

<bean class="...HelloWorldTasklet" />

</constructor-arg>

</bean>

</list>

</property>

</bean>

“Hello World!” - configuration<bean id="jobConfiguration" parent="simpleJob">

<property name="name" value="helloWorldJob" />

<property name="steps">

<list>

<bean id="step1" parent="simpleStep">

<constructor-arg>

<bean class="...HelloWorldTasklet" />

</constructor-arg>

</bean>

</list>

</property>

</bean>

Simple job - taskletpublic class SimpleTasklet implements Tasklet {

private InputSource inputSource;private OutputSource outputSource;

public ExitStatus execute() throws Exception {Object data = inputSource.read();

if (data != null) {outputSource.write(data);return ExitStatus.CONTINUABLE;

}return ExitStatus.FINISHED;

}public void setInputSource(InputSource inputSource) {

this.inputSource = inputSource;}public void setOutputSource(OutputSource outputSource) {

this.outputSource = outputSource;}

}

Simple job - taskletpublic class SimpleTasklet implements Tasklet {

private InputSource inputSource;private OutputSource outputSource;

public ExitStatus execute() throws Exception {Object data = inputSource.read();

if (data != null) {outputSource.write(data);return ExitStatus.CONTINUABLE;

}return ExitStatus.FINISHED;

}public void setInputSource(InputSource inputSource) {

this.inputSource = inputSource;}public void setOutputSource(OutputSource outputSource) {

this.outputSource = outputSource;}

}

Simple job - taskletpublic class SimpleTasklet implements Tasklet {

private InputSource inputSource;private OutputSource outputSource;

public ExitStatus execute() throws Exception {Object data = inputSource.read();

if (data != null) {outputSource.write(data);return ExitStatus.CONTINUABLE;

}return ExitStatus.FINISHED;

}public void setInputSource(InputSource inputSource) {

this.inputSource = inputSource;}public void setOutputSource(OutputSource outputSource) {

this.outputSource = outputSource;}

}

Simple job - configuration<bean id="jobConfiguration" parent="simpleJob">

<property name="name" value="simpleTaskletJob" />

<property name="steps">

<list>

<bean id="step1" parent="simpleStep">

<constructor-arg>

<bean class="...SimpleTasklet">

<property name="inputSource" ref="inputSource" />

<property name="outputSource" ref="outputSource" />

</bean>

</constructor-arg>

</bean>

</list>

</property>

</bean>

Simple job – input source<bean id=“inputSource" class="...SqlCursorInputSource“

scope="step" >

<aop:scoped-proxy />

<property name="dataSource" ref="dataSource" />

<property name="sql"

value="SELECT id, quantity, price, customer from TRADE" />

<property name="mapper">

<bean class="...TradeRowMapper" />

</property>

</bean>

Simple job – input source<bean id=“inputSource" class="...SqlCursorInputSource“

scope="step" >

<aop:scoped-proxy />

<constructor-arg>

<ref bean="dataSource" />

</constructor-arg>

<property name="sql"

value="SELECT id, quantity, price, customer from TRADE" />

<property name="mapper">

<bean class="...TradeRowMapper" />

</property>

</bean>

Simple job – output source<bean id="outputSource" class="...FlatFileOutputSource“

scope="step" >

<aop:scoped-proxy />

<property name="resource" value="file:out.txt" />

</bean>

Common job - configuration<bean id="jobConfiguration" parent="simpleJob">

<property name="name" value="commonJob" /><property name="steps"> <bean id="step1" parent="simpleStep">

<constructor-arg> <bean class="...tasklet.RestartableItemProviderTasklet">

<property name="itemProvider"> <bean class="...tasklet.support.InputSourceItemProvider"> <property name="source" ref="sqlInputSource" /> </bean> </property> <property name="itemProcessor"> <bean

class="...tasklet.support.OutputSourceItemProcessor"> <property name="source" ref="xmlOutputSource" /> </bean> </property> </bean></constructor-arg>

</bean></property>

</bean>

Common job – tasklet<bean class="...tasklet.RestartableItemProviderTasklet">

<property name="itemProvider"> <bean class="...tasklet.support.InputSourceItemProvider">

<property name="source" ref="sqlInputSource" /> </bean></property>

<property name="itemProcessor"> <bean class="...tasklet.support.OutputSourceItemProcessor">

<property name="source" ref="xmlOutputSource" /> </bean></property>

</bean>

Common job – tasklet<bean class="...tasklet.RestartableItemProviderTasklet">

<property name="itemProvider">

<bean class="...tasklet.support.InputSourceItemProvider">

<property name="source" ref="sqlInputSource" />

</bean>

</property>

<property name="itemProcessor">

<bean class="...tasklet.support.OutputSourceItemProcessor">

<property name="source" ref="xmlOutputSource" />

</bean>

</property>

</bean>

Common job – tasklet<bean class="...tasklet.RestartableItemProviderTasklet">

<property name="itemProvider">

<bean class="...tasklet.support.InputSourceItemProvider">

<property name="source" ref="sqlInputSource" />

</bean>

</property>

<property name="itemProcessor">

<bean class="...tasklet.support.OutputSourceItemProcessor">

<property name="source" ref="xmlOutputSource" />

</bean>

</property>

</bean>

Samples overview Samples project contains simple batch

jobs illustrating various capabilities of the Spring-Batch framework

See the folder src/main/resources/jobs for job configuration files

See src/test/java, package org.springframework.batch.sample for tests which launch the jobs and check the expected results

simpleTaskletJob.xml Straightforwardly implemented Tasklet,

similar to the “Simple Job” example All-in-one solution to help understand

tasklet’s execution logic Standard solutions are more modular,

which makes them more flexible and reusable, but also less straightforward to understand

fixedLengthImportJob.xml Clean separation of reading input and

processing data (standard from now on) Typical scenario of importing data from a

fixed-length file to database Custom DAO used for output

multilineOrderJob.xml Handling of complex file format, both

reading input and writing output Single record spans multiple lines and has

nested records Custom ItemProvider and ItemProcessor

implementations handling non-standard file format

tradeJob.xml shows a reasonably complex scenario,

that would resemble the real-life usage of the framework

3 steps: trade records are imported from file to

database customer account balance is adjusted report about customers is exported to a file

compositeProcessorSample.xml Parallel writing to multiple outputs Example usage of composite

ItemProcessor with an injected list of ItemProcessors

restartSample.xml Simulates restart scenario, where the job

crashes on first run and succeeds after being restarted

Uses ‘hacked’ tasklet that throws exception after reading a given number of records