How to get access to job parameters from ItemReader in Spring Batch

Question

This is part of my job xml    lt job id  foo  job-repository  job-repository  gt     lt step id  bar  gt       lt tasklet transaction-manager  transaction-manager  gt         lt chunk commit-interval  1          reader  foo-reader  writer  foo-writer          gt       lt  tasklet gt     lt  step gt   lt  job gt    This is the item reader   import org springframework batch item ItemReader  import org springframework beans factory annotation Value  import org springframework stereotype Component   Component  foo-reader   public final class MyReader implements ItemReader lt MyData gt       Override   public MyData read   throws Exception                    Value    jobParameters  fileName        public void setFileName final String name                      This is what Spring Batch is saying in runtime   Field or property  jobParameters  cannot be found on object of  type  org springframework beans factory config BeanExpressionContext    What s wrong here  Where I can read more about these mechanisms in Spring 3 0

User · Answer

While executing the job we need to pass Job parameters as follows:

JobParameters jobParameters= new JobParametersBuilder().addString("file.name", "filename.txt").toJobParameters();   
JobExecution execution = jobLauncher.run(job, jobParameters);

by using the expression language we can import the value as follows:

 #{jobParameters['file.name']}

User · Answer

To be able to use the jobParameters I think you need to define your reader as scope  step   but I am not sure if you can do it using annotations   Using xml-config it would go like this    lt bean id  foo-readers  scope  step    class     MyReader  gt     lt property name  fileName  value    jobExecutionContext  fileName       gt   lt  bean gt    See further at the Spring Batch documentation   Perhaps it works by using  Scope and defining the step scope in your xml-config    lt bean class  org springframework batch core scope StepScope    gt

User · Answer

Did you declare the jobparameters as map properly as bean   Or did you perhaps accidently instantiate a JobParameters object  which has no getter for the filename   For more on expression language you can find information in Spring documentation here

User · Answer

If you want to define your ItemReader instance and your Step instance in a single JavaConfig class  You can use the  StepScope and the  Value annotations such as    Configuration public class ContributionCardBatchConfiguration       private static final String WILL BE INJECTED   null       Bean     StepScope    public FlatFileItemReader lt ContributionCard gt  contributionCardReader  Value    jobParameters  fileName     String contributionCardCsvFileName                        Bean    Step ingestContributionCardStep ItemReader lt ContributionCard gt  reader            return stepBuilderFactory get  ingestContributionCardStep                      lt ContributionCard  ContributionCard gt chunk 1                    reader contributionCardReader WILL BE INJECTED                     writer contributionCardWriter                      build              The trick is to pass a null value to the itemReader since it will be injected through the  Value    jobParameters  fileName      annotation   Thanks to Tobias Flohre for his article   Spring Batch 2 2     JavaConfig Part 2  JobParameters  ExecutionContext and StepScope

User · Answer

As was stated  your reader needs to be  step  scoped  You can accomplish this via the  Scope  step   annotation  It should work for you if you add that annotation to your reader  like the following   import org springframework batch item ItemReader  import org springframework beans factory annotation Value  import org springframework stereotype Component    Component  foo-reader    Scope  step   public final class MyReader implements ItemReader lt MyData gt       Override   public MyData read   throws Exception                     Value    jobParameters  fileName        public void setFileName final String name                      This scope is not available by default  but will be if you are using the batch XML namespace  If you are not  adding the following to your Spring configuration will make the scope available  per the Spring Batch documentation    lt bean class  org springframework batch core scope StepScope    gt

User · Answer

Complement with an additional example  you can access all job parameters in JavaConfig class    Bean  StepScope public ItemStreamReader lt GenericMessage gt  reader  Value    jobParameters    Map lt String Object gt  jobParameters

User · Answer

Pretty late  but you can also do this by annotating a  BeforeStep method    BeforeStep     public void beforeStep final StepExecution stepExecution            JobParameters parameters   stepExecution getJobExecution   getJobParameters              use your parameters

[java] How to get access to job parameters from ItemReader, in Spring Batch?

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