Access Job Parameter in Custom ItemProcessor

Question

I am implementing a custom ItemProcessor<I, O> in spring batch for processing data from a Rest api .

I want access some values from jobParameter inside my ItemProcessor class . Any suggestion on how to do that ?

In Tasklet we can access JobParameter but not sure how to do in ItemProcessor .

MyItemProcessor.java

@Component  
public class MyItemProcessor implements ItemProcessor<User, UserDetails> {
    

    @Override
    public UserDetails process(User user) throws Exception {
        // access values from job parameter here

        return null;
    }
}

Answer 1

You can make your item processor step-scoped and inject job parameters in it. The following is one way of doing that:

@Component
@StepScope  
public class MyItemProcessor implements ItemProcessor<User, UserDetails> {
    
    @Value("#{jobParameters}")
    private JobParameters jobParameters;

    @Override
    public UserDetails process(User user) throws Exception {
        // access values from job parameter here

        return null;
    }
}

You could also inject a specific parameter if you want with something like the following:

@Component
@StepScope  
public class MyItemProcessor implements ItemProcessor<User, UserDetails> {
    
    @Value("#{jobParameters['myParameter']}")
    private String myParameter;

    @Override
    public UserDetails process(User user) throws Exception {
        // use myParameter as needed here

        return null;
    }
}

Since field injection is not recommended, you can inject job parameters in your item processor when you define it as a bean, something like:

// Note how nothing related to Spring is used here, and the processor can be unit tested as a regular Java class
public class MyItemProcessor implements ItemProcessor<User, UserDetails> {
    
    private String myParameter;

    public MyItemProcessor(String myParameter) {
        this.myParameter = myParameter;
    }

    @Override
    public UserDetails process(User user) throws Exception {
        // use this.myParameter as needed here

        return null;
    }
}

Once that in place, you can declare your item processor bean as follows:

@Bean
@StepScope
public MyItemProcessor itemProcessor(@Value("#{jobParameters['myParameter']}") String myParameter) {
    return new MyItemProcessor(myParameter);
}

Fore more details about scoped beans, please check the documentation here: Late Binding of Job and Step attributes.