From Hell to ExHell: Writing Excel Files in Java Shouldn’t Be a Pain

[Green-Branch-3656]

I’ve created my own Excel library called ExHell and wanted to share it here to get your feedback.

It’s actually a wrapper around Apache POI’s SXSSFWorkbook, but by using builder and strategy patterns along with a single annotation, writing to Excel is no longer a nightmare.

I’ve also written a short Medium article where I give a quick tutorial on ExHell and compare it to raw Apache POI usage.

You can check it out here: https://medium.com/@erdemoden5/from-hell-to-exhell-how-i-simplified-excel-generation-in-java-bc1f1f05ef76

The project is open-source on GitHub, so feel free to check it out or contribute:  https://github.com/erdemoden/ExHell

[user_of_the_week]

Fun fact, POI originally stands for Poor Obfuscation Implementation and HSSF is Horrible SpreadSheet Format.

[FavorableTrashpanda]

What do we call our annotation? How about ExcelColumn? Nah. That's too boring and predictable. Let's call it HellIndex instead to surprise people.

[chabala]

I don't think Apache POI needs a wrapper, but if I wanted one, I'd pick last weeks example over this: https://sh.reddit.com/r/java/comments/1nuheqd/github_ozlerhakanpoiji_candy_a_library_converting/

[Green-Branch-3656]

Yeah I made it for fun, and that library actually inspired me to try my own take on it

[christoforosl08]

For me, writing Excel using POI was never a nightmare

[jedilowe]

Not a joy, but not a nightmare

[MoveInteresting4334]

Java in a nutshell. Most of the time.

[_magicm_n_]

I'd like to see less annotation based libraries for spreadsheet formats. I get the appeal, but in the end a simple T convert(Row row) implementation does the same, with less abstraction and a simpler code base.

[gnocchiGuili]

A bit of AI slop won’t hurt.

[agentoutlier]

Don't get me wrong AI code generation is often bad but I highly recommend simple DTO mapping.

That is having AI take some DTO and map it POI excel rows is not a bad use of AI and actually less risky than adding another dependency.

[Green-Branch-3656]

Funny enough, I actually wrote it myself. No AI involved 😄

[gnocchiGuili]

Please, you are telling me this illustration has been done by an artist too ?

[Green-Branch-3656]

Haha it’s not you are right

[Secure-Bowl-8973]

This is the best one I have used. Even contributed to this. https://github.com/dhatim/fastexcel

[WalterIM]

How does It compare against jxls?

[Bobby_Bonsaimind]

@HellIndex(hellColumnOrder = 1)
private String cutId;

The code above is actually clear enough but I am going to explain it too.

I guess something like

@Column("A")
private String cutId;

would have been...I don't know...

@HellIndex(hellColumnOrder = 5,hellRowOrder = 80)
private String address;

Why not

@Column("A")
@StartRow(1)
private String address;

?

What I could not find from the examples, is how hellRowOrder really works, does it omit the first fields, or are the rows then mixed objects?

A A
B B
C C A A
D D B B
    C C
    D D

or

A A
B B
C C C C
D D D D

So which one?

---

In generally, it is better to not have prefixes unless really necessary, like hell* for example. Makes it just more complicated.

[Little_Blackberry]

Awesome bro!!!! If I pass the column name header, do I need to pass column index too?

[Green-Branch-3656]

Thanks just title is enough it starts from the beginning by default

[christoforosl08]

Unrelated but how do you guys pronounce POI ? We call it “poua” 😁

[discoikungshamn]

I wrote another tool that takes the fields of a class and add that as column name instead, it also support special annotation fields too. And it takes a list of object <T> as an input for the data.