pass job parameters to custom writer Spring batch - spring

Question

I have a custom writer with a FlatFileItemWriter and i want to pass a job parameter( a output file) defined in the main class
How can i deal with this ?
Thank you very much
CustomWriter
public class PersonItemWriter implements ItemWriter<Person> {
private FlatFileItemWriter<String> flatFileItemWriter = new FlatFileItemWriter<String>();
private Resource resource;
#Override
public void write(List<? extends Person> personList) throws Exception {
flatFileItemWriter.setResource(new FileSystemResource(resource.getFile()));
PassThroughLineAggregator<String> aggregator = new PassThroughLineAggregator<String();
flatFileItemWriter.setLineAggregator(aggregator);
flatFileItemWriter.open(new ExecutionContext());
flatFileItemWriter.write(Arrays.asList(aggregator.aggregate("test")));
flatFileItemWriter.close();
}
public void setResource(Resource resource) {
this.resource = resource;
}
}
Launcher
JobLauncher jobLauncher = (JobLauncher) applicationContext.getBean("jobLauncher");
Job job = (Job) applicationContext.getBean("personJob");
/* Parameters sent to job */
JobParametersBuilder jobParametersBuilder = new JobParametersBuilder();
jobParametersBuilder.addString("outputFileName", "file:" + personFile); // pass this to the itemWriter
configuration job xml
<bean id="personWriter" class="com.dev.writer.PersonItemWriter" scope="step>
<property name="resource" value="#{jobParameters[outputFileName]}" />
</bean>

Answer 1

You have to declare the bean with either step scope or job scope so you can have late binding of a property based on the job parameter:
<bean id="personWriter" class="com.dev.writer.PersonItemWriter" scope="step">
<property name="resource" value="#{jobParameters[outputFileName]}" />
</bean>
These scopes are not available by default, you need to include them either by either using the batch namespace or defining the following bean:
<bean class="org.springframework.batch.core.scope.StepScope" />
Update:
Here's the complete writer:
public class PersonItemWriter implements ItemWriter<Person> {
FlatFileItemWriter<String> flatFileItemWriter = new FlatFileItemWriter<String>();
private Resource resource;
#Override
public void write(List<? extends Person> personList) throws Exception {
flatFileItemWriter.setResource(resource);// how the pass the job parameter file here
PassThroughLineAggregator<String> aggregator = new PassThroughLineAggregator<String();
flatFileItemWriter.setLineAggregator(aggregator);
aggregator.aggregate("test"); // do not save in output file
}
public FlatFileItemWriter<String> getFlatFileItemWriter() {
return flatFileItemWriter;
}
public void setFlatFileItemWriter(FlatFileItemWriter<String> flatFileItemWriter) {
this.flatFileItemWriter = flatFileItemWriter;
}
public void setResource(Resource resource) {
this.resource = resource;
}
}

Answer 2

You can define a HashMap and use this HashMap instead of jobParameter.
<bean id="paramBean" class="java.util.HashMap"/>
<bean id="personWriter" class="com.dev.writer.PersonItemWriter" scope="step">
<property name="resource" value="#{paramBean[outputFileName]}" />
</bean>
Write the setter method in ItemWriter and set the values in the HashMap.
private HashMap paramBean;
public void setParamBean(HashMap paramBean) {
this.paramBean= paramBean;
}
paramBean.set(<key>,<value>);