Easiest way to compare two Excel files in Java?

Question

I'm writing a JUnit test for some code that produces an Excel file (which is binary). I have another Excel file that contains my expected output. What's the easiest way to compare the actual file to the expected file?

Sure I could write the code myself, but I was wondering if there's an existing method in a trusted third-party library (e.g. Spring or Apache Commons) that already does this.

Answer 1

You might consider using my project simple-excel which provides a bunch of Hamcrest Matchers to do the job.

When you do something like the following,

assertThat(actual, WorkbookMatcher.sameWorkbook(expected));

You'd see, for example,

java.lang.AssertionError:
Expected: entire workbook to be equal
     but: cell at "C14" contained <"bananas"> expected <nothing>,
          cell at "C15" contained <"1,850,000 EUR"> expected <"1,850,000.00 EUR">,
          cell at "D16" contained <nothing> expected <"Tue Sep 04 06:30:00">
    at org.hamcrest.MatcherAssert.assertThat(MatcherAssert.java:20)

That way, you can run it from your automatted tests and get meaningful feedback whilst you're developing.

You can read more about it at this article on my site