This is a basic guide to get you started with Spring Batch Framework. The framework has alot to get your head around.

Key Terms with references

• Job – Contains steps for the process execution (describes what job is and how it is executed). It is entire set of batch work.
• Job Instance – Represents the given job during the execution process (organises the job process with job parameters)
• Job Parameters – are type properties that are parameters for the job instance.
• Job Execution – is what happend during job run (i.e. status, failures etc.) – Each run of Job Instance results in Job Execution.
• Step Execution – is a run of a single step execution in Job Instance.
• Job Repository – represents a persistent store (i.e. database) for the jobs to run.
• Tasklet – is to setup or cleanup resources before the main business logic is executed.
• Job Launcher – is responsible for starting a Job with given job parameters

Example

We will be using SimpleJobLauncher that relies on a TaskExecutor to launch the jobs. If there is no specific TaskExecutor is set then a SyncTaskExecutor is used. We will use the SimpleJobRepository implementation which requires a set of execution Daos to store its information.

Tasklet Example

public class PrintTasklet implements Tasklet
{
private String message;
public void setMessage(String message)
{
this.message = message;
}
public ExitStatus execute() throws Exception
{
System.out.println("**** "+message+" ******");
return ExitStatus.FINISHED;
}
}

Luncher Context Example

<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
<bean id="jobLauncher" class="org.springframework.batch.core.launch.support.SimpleJobLauncher">
<property name="jobRepository" ref="jobRepository"/>
</bean>
<bean id="jobRepository" class="org.springframework.batch.core.repository.support.SimpleJobRepository">
<constructor-arg>
<bean class="org.springframework.batch.core.repository.dao.MapJobInstanceDao"/>
</constructor-arg>
<constructor-arg>
<bean class="org.springframework.batch.core.repository.dao.MapJobExecutionDao" />
</constructor-arg>
<constructor-arg>
<bean class="org.springframework.batch.core.repository.dao.MapStepExecutionDao"/>
</constructor-arg>
</bean>
</beans>

Job XML Example

 
<bean id="hello" class="eg.spring.batch.PrintTasklet">
<property name="message" value="Hello"/>
</bean>
<bean id="space" class="eg.spring.batch.PrintTasklet">
<property name="message" value=" "/>
</bean>
<bean id="world" class="eg.spring.batch.PrintTasklet">
<property name="message" value="World!"/>
</bean>
<bean id="taskletStep" abstract="true"
class="org.springframework.batch.core.step.tasklet.TaskletStep">
<property name="jobRepository" ref="jobRepository"/>
</bean>
<bean id="simpleJob" class="org.springframework.batch.core.job.SimpleJob">
<property name="name" value="simpleJob" />
<property name="steps">
<list>
<bean parent="taskletStep">
<property name="tasklet" ref="hello"/>
</bean>
<bean parent="taskletStep">
<property name="tasklet" ref="space"/>
</bean>
<bean parent="taskletStep">
<property name="tasklet" ref="world"/>
</bean>
</list>
</property>
<property name="jobRepository" ref="jobRepository"/>
</bean>
</beans>

Running the Example

Download spring batch version 1.2 and add all the jars into the classpath. Also add in launcherContext.xml and simpleJob.xml in classpath as well as PrintTaskLet.class or in a jar file. Ensure that PrintTasklet class is in package “eg.spring.batch”.
Then from command prompt:
java org.springframework.batch.core.launch.support.CommandLineJobRunner simpleJob.xml simpleJob

Resourcess

• http://static.springsource.org/spring-batch/