How to use ingest attachment plugin to index and store the pdfs in elastic search using spring boot

I need to store the pdfs in elastic search using spring boot microservices. I want some sample how the ingest plugin works in storing the pdfs
I would really appreciate the help.Thanks

That's a duplicate of How to index and store pdf file in elastic search using spring boot?

Let's keep the conversation in one place unless it's a different question.

Thanks.