Hello Listing all external links in .xlsx files is easy, just call XSSFWorkbook.getExternalLinksTable() and iterate over them. No alternative in HSSFWorkbook currently exists. It would be very nice to implement this functionality and offer it at the abstract Workbook level. See also this thread with the current very dirty workaround and suggestion that this enhancement request should be created: http://stackoverflow.com/questions/26758099/how-to-extract-a-list-of-external-references-from-a-excel-file
The two file formats store external references in very different ways, so I'm not sure how possible it is to offer a common interface across them That said... If you can come up with a good interface, that will work for both, and exposes useful information, we can certainly look at adding it!
I think this is now fixed via bug 58572 *** This bug has been marked as a duplicate of bug 58572 ***
bug 58572 creates a common interface for Hyperlinks (URLs, emails, document links, and files). It does not provide a common interface for External Links. From XSSFWorkbook java docs: getExternalLinksTable The external links table specifies details of named ranges etc * that are referenced from other workbooks, along with the last seen * values of what they point to. I'm reopening this bug because I'm assuming Dominique wasn't looking for common Hyperlink support.
Yep, good catch, it seems I did not look too closely here!