pass job parameters to custom writer Spring batch

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> 

Solution

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;
    }
}

Comments

[ulquiorra]

Thank you very much but your answer works for a default writer not my customized one because of the resource property ( i got the error "Invalid property 'resource' of bean class [com.dev.writer.PersonItemWriter]: Bean property 'resource' is not writable... ")

[Sergi Almar]

Update your custom writter and add the resource property with the corresponding setter

[ulquiorra]

Thanks i have updated my code but it does not save into the outputFile. When i check in debug mode , the flatFileItemWriter properties contains a resource of type URLResource which contains("file:C:/temps/outPutFolder.txt"). Do i miss something ? Thank you very much

[Sergi Almar]

Seems you are missing the scope="step" in the bean definition

[ulquiorra]

It was in my code. I just forget to put it here sorry . but i still have the issue . probably because the file is considered as URLResource ? Thank you

[Sergi Almar]

I've updated the response with the writer, inject the property resource instead of flatFileItemWriter.resource

[ulquiorra]

Thank you very much , i really appreciate your help and patience . I will test this by monday :)

[ulquiorra]

It works thanks . However i needed to add flatFileItemWriter.open() and flatFileItemWriter.write() in order to write in my file. I updated my code. Thank you very much :)

[user1912935]

tried above it is throwing java.lang.IllegalStateException: Cannot bind to partial key %{paramBean[outputFileName]} exception...