Java excel api jar download

Asked 7 years, 2 months ago. Active 6 years, 4 months ago. Viewed 19k times. I am trying to add a function to my web app which lets the users download an excel file. If I open it with microsoft excel, I get a popup with the message: "the file format and extension of don't match. And the excel file is empty. What am I doing wrong? Improve this question.

MeesterPatat MeesterPatat 2, 7 7 gold badges 27 27 silver badges 51 51 bronze badges. Are you sure the excel file is valid before attemting to download it? Can it be it is already corrupted before the process? Yes i'm sure about that.

Well, one thing is for sure, the code you posted surely does not modify or corrupt your Excel file. What is the size of your file? Is it be very big, perhaps? Why don't you read the file as chunk instead of per bytes? Find centralized, trusted content and collaborate around the technologies you use most. Connect and share knowledge within a single location that is structured and easy to search. I think SpringMVC and vertx.

The response is a binary file, not a text. Hence it must loaded by an InputStream, and written by an OutputStream. Readers and Writers are for Unicode text and always imply a charset conversion for the binary bytes. Which would corrupt things or at least make them slow. That Excel internally uses UTF-8? Should not be needed. Nice to reply to you. First, you ought to consider the MVN package to a jar lead to your excel that can not open. Finally, you can try to movie the excel at the jar's same file directory to access.

I think that is OK. My best to you. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. The Apache POI team is pleased to announce the release of 5. Several dependencies were updated to their latest versions to pick up security fixes and other improvements.

A summary of changes is available in the Release Notes. A full list of changes is available in the change log.

People interested should also follow the dev list to track progress. This issue was fixed a few years ago but on review, we decided we should have a CVE to raise awareness of the issue.

XMLBeans 4. References: XML external entity attack. Mitigation: Apache POI 4. Affected users are advised to update to Apache POI 4. Featured are a handful of bug fixes. People interested should also follow the POI dev list to track progress.