it is a spring-boot project using maven.
here I add some randon methods for learning propouse.
there is 2 classes related to an example of how use opencsv and apache.poi for read csv and excel files respectively
more are comming
https://stackoverflow.com/questions/42455154/export-java-hashmap-to-xlsx
https://mkyong.com/java/apache-poi-reading-and-writing-excel-file-in-java/
https://www.baeldung.com/convert-file-to-input-stream
https://www.csvreader.com/java_csv_samples.php
http://opencsv.sourceforge.net/#reading_into_beans
https://mkyong.com/java/how-to-read-and-parse-csv-file-in-java/