Reference POC projects to work with excel files using Apache POI library and Java Spring-boot
All Proof of concepts are deployed to heroku with their links and sample videos included in their respective README.md file
Proof of concepts included in this repo (Summary)
Create excel file with single sheet from database records
Insert 300 dummy employees records in H2 DB on startup using @PostConstruct
endpoint exposed to download created excel sheet from the inserted records at runtime
Create excel file with multiple sheet from database records
insert super_heroes from different comics in DB at startup (Marvel, Detective Comics)
endpoint exposed to download multiple sheet excel file created at runtime
each sheet contains records of super_heroes from one comic
one sheet for all superheroes from marvel comics, one for DC and so on.
Validate data inside excel sheet for errors and return errors as List.of(String)
endpoint exposed for user to download excel template (required columns)
user fills in data (rows) to downloaded template
exception is thrown is file extension or format(column names and order) is different
the errors include leaving cells blank, duplicate email-id, wrong email-id, invalid number type etc
each row is validated for errors, if errors exists a list is returned detailing out the error messages along with it's cell position
Validate data inside excel sheet for errors and detail out errors in given excel file itself and return the same
same as above (first 4)
each cell of each row is validated for errors and if a cell is found to have any error it is colored in RED
a new sheet in the same excel file is created detailing out the error messages (type) and the cell position (row, column)
the above modified file is returned (downloaded automatically to users screen) if errors exists
Read data from excel sheet to database
endpoint exposing to download required excel sheet template (required columns)
sheet is validated for errors, if no errors are found a unique 6 digit code and the hex of the validated file is generated, the code is returned as response
the code is stored in a cache as key with the validated file's hex being it's value
user hits /employee/bulk-upload API with given code and validated file (error thrown if code is invalid or file other than the validated one is provided)
each row is read from the given sheet and corresponding records are created in the database
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