how to send a custom object as Job Parameter in Spring Batch?

Question

I have a requirement of sending a Custom Object to the Spring Batch Job , where this Object is used continuously used by the Item Processor for the business requirement.

How can we send custom object from outside to the Job Context. This Object changes from Job to Job and generated at runtime depending on Business case.

How can send this as a Job Parameter? or is there any way that i can set this Object to the respective Job ?

can overriding Spring JobParameter help me in any way? or are there any Big issues as an outcome of this Overriding behaviour ?

Answer 1

I have summarized reasons why you cannot send object as JobParameter in this question. There are couple of ideas on that question how you can do it.

TL:TR: I think best way would be either to create table in DB which stores Object and pass id of that record as JobParameter or to serialize Object to json and pass it as String in job as JobParameter. If you go with second option be aware that string_val is stored in DB as varchar 250 so limit is 250 characters.

Answer 2

Use the below class to send CustomObject.

public static class CustomJobParameter<T extends Serializable> extends JobParameter {
        private T customParam;
        public CustomJobParameter(T customParam){
            super(UUID.randomUUID().toString());//This is to avoid duplicate JobInstance error
            this.customParam = customParam;
        }
        public T getValue(){
            return customParam;
        }
    }

===========================

Usage:

1. Sending parameter:

   JobParameters paramJobParameters = new JobParametersBuilder().addParameter("customparam", new CustomJobParameter<MyClass>(myClassReference)).toJobParameters();

2. Retrieving parameter:

   MyClass myclass = (MyClass)jobExecution.getJobParameters().getParameters().get("customparam").getValue();