Setting a properties file in Spring Batch via a JobParameter

Question

I have three different .properties files in a Spring Batch project, and I'm trying to set which .properties file should be used as a JobParameter. I'd like to be able to run the job like so:

java CommandLineJobRunner context.xml jobName region=us

The region should specify which .properties file should be used. The problem is getting the context to recognize the JobParameter. I've tried the following to no avail:

<context:property-placeholder location="classpath:batch.#{jobParameters['region']}.properties"/>

And also:

<util:properties id="batchProperties" location="classpath:batch.#{jobParameters['region']}.properties"></util:properties>

I had heard that adding scope="step" could fix similar issues, but I tried adding that to both of the above solutions and still had exceptions.

I think I'm missing a fundamental idea of why I can't get this working, but I'm unable to figure out what that idea is.

If anyone has any suggestions on getting this working and/or explaining why my previous approaches failed, I'd appreciate it.

Answer 1

This is not the right way to proceed (it is impossible do what you are trying to do).
You have to think that jobParameters is available only when a job is running and only for its composing steps marked with scope="step" (and not <context:property-placeholder> nor <util:properties> has a step attribute).
A way for solving the problem is to load properties file in job's execution context before first step is running with a listener:

public class PropertyLoaderJobExecutionListener extends StepExecutionListenerSupport {
  Properties countryProperties;

  public void setCountryProperties(Properties pfb) {
    this.countryProperties = pfb;
  }

  @Override
  public void beforeStep(StepExecution stepExecution) {
    super.beforeStep(stepExecution);
    // Store property file content in jobExecutionContext with name "batchProperties"
    stepExecution.getJobExecution().getExecutionContext().put("batchProperties", countryProperties);
  }
}

in your job.xml

<bean id="loadPropertiesListener" class="PropertyLoaderJobExecutionListener" scope="step">
  <property name="pfb">
    <bean class="org.springframework.beans.factory.config.PropertiesFactoryBean">
      <property name="location" value="classpath:batch.#{jobParameters['region']}.properties" />
    </bean>
  </property>
</bean>

and register this listener in your first step (you can't do that in your JobExectionListsner.beforeJob() because there isn't a scope="job" for now and late-binding of #{jobParameters['region']} value is not available).

To access your data with spEL use this syntax:

#{jobExecutionContext.get('batchProperties').getProperty('language')}

or a better syntax to access properties (IDK spEL so good, sorry).

Hope to be clear and can help to solve your problem.

EDIT (full code of my working job.xml):

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:util="http://www.springframework.org/schema/util"
       xsi:schemaLocation="http://www.springframework.org/schema/batch http://www.springframework.org/schema/batch/spring-batch-2.2.xsd
        http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-util-3.1.xsd
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd">
    <job id="sourceJob" xmlns="http://www.springframework.org/schema/batch">
        <step id="step1">
            <tasklet ref="getRemoteFileTasklet" />
            <listeners>
                <listener ref="loadPropertiesListener" />
            </listeners>
        </step>
    </job>
    <bean id="loadPropertiesListener" class="PropertyLoaderJobExecutionListener" scope="step">
        <property name="pfb">
            <bean class="org.springframework.beans.factory.config.PropertiesFactoryBean">
                <property name="location" value="classpath:batch.#{jobParameters['region']}.properties" />
            </bean>
        </property>
    </bean>
    <bean id="getRemoteFileTasklet" class="GetRemoteFileTasklet" />