Set hashmap in JobParameter in spring boot - spring-boot

Question

I am working on creating excel file from data, for that I have created job. I want to set hashmap to the jobparameter so that I can use it in MyReader class, I have created CustomJobParameter Class.
Below code you can find to get the job parameters :
Get Job Parameters :
public JobParameters createJobParam (MyRequest request) {
final JobParameters parameters = new JobParametersBuilder()
.addString("MyParam1", request.getReportGenerationJobId())
.addString("MyParam2", request.getSessionId())
.addLong("time", System.currentTimeMillis())
.addParameter(
"MyObject",
new MyUtils.CustomJobParameter(request.getHsSlideArticles())
)
.toJobParameters();
return JobParameters;
}
CustomJobParameter Class written in MyUtils class:
public static class CustomJobParameter<T extends Serializable> extends JobParameter {
private HashMap customParam;
public CustomJobParameter (HashMap slideArticles) {
super("");
this.customParam = customParam;
}
public HashMap getValue () {
return customParam;
}
}
But while I am setting using custom parameters, it setting blank string, not object I am passing.
How can I pass the hashmap to my reader.

Answer 1

According to the documentation for JobParameter, a JobParameter can only be String, Long, Date, and Double.
https://docs.spring.io/spring-batch/docs/current/api/org/springframework/batch/core/JobParameter.html
Domain representation of a parameter to a batch job. Only the following types can be parameters: String, Long, Date, and Double.
The identifying flag is used to indicate if the parameter is to be
used as part of the identification of a job instance.
Therefore you can not extend JobParameter and expect it to work with HashMap.
However there is another option, JobParameters:
https://docs.spring.io/spring-batch/docs/current/api/org/springframework/batch/core/JobParameters.html
https://docs.spring.io/spring-batch/docs/current/api/org/springframework/batch/core/JobParametersBuilder.html
You could create a Map<String, JobParameter> instead :
Example:
new JobParameters(Maps.newHashMap("yearMonth", new JobParameter("2021-07")))
and then use JobParametersBuilder addJobParameters in your createJobParam to simply add all your Map<String, JobParameter> records:
addJobParameters(JobParameters jobParameters) //Copy job parameters into the current state.
So your method will look like:
public JobParameters createJobParam (MyRequest request) {
final JobParameters parameters = new JobParametersBuilder()
.addString("MyParam1", request.getReportGenerationJobId())
.addString("MyParam2", request.getSessionId())
.addLong("time", System.currentTimeMillis())
.addParameters(mayHashMapThatHas<String,JobParameter>)
.toJobParameters();
return JobParameters;
}