How to get JobParameter and JobExecutionContext in the ItemWriter?

Question

I want to retrieve JobParameter and JobExecutionContext object in my ItemWriter class. How to proceed?

I tried implementing StepExecutionListener through which I am just calling the parent class methods. But it is not succeeding.

Thanks in advance.

Answer 1

Implementing StepExecutionListener is one way. In fact that's the only way in Spring Batch 1.x.

Starting from Spring Batch 2, you have another choice: You can inject whatever entries in Job Parameters and Job Execution Context to your item writer. Make your item writer with step scope, then make use of expression like #{jobParameters['theKeyYouWant']} or #{jobExecutionContext['someOtherKey']} for value injecting to you item writer.

Answer 2

Use the @BeforeStep annotation to call a method before step processing.

//From the StepExecution get the current running JobExecution object.
public class MyDataProcessor implements ItemProcessor<MyDataRow, MyDataRow> {
    private JobExecution jobExecution;

    @BeforeStep
    public void beforeStep(StepExecution stepExecution) {
        jobExecution = stepExecution.getJobExecution();
    }
}

Answer 3

To add to Adrian Shum's answer, if you want to avoid each job parameter to be injected as a class property, you can directly inject the Map of JobParameters as follows:

@Value("#{jobParameters}")
private Map<String, JobParameter> jobParameters;

Answer 4

If you are using Spring Configuration file, you can access the StepExecution object with:

<bean id="aaaReader" class="com.AAAReader" scope="step">
    <property name="stepExecution" value="#{stepExecution}" />
</bean>

In AAAReader class you need to create the proper field and a setter:

private StepExecution stepExecution;

public void setStepExecution(final StepExecution stepExecution) {
    this.stepExecution = stepExecution;
}

Same for Processor and Writer classes.