How can you get the exact size of a file in bytes.

**J-Live** · 10-27-2008, 04:40 AM

So, if a file is 308.81MB, how can I get the exact size of the file in bytes? I need to get the exact size of the file because Randomaccessfile's setLength method only excepts long values. That will cause the data to become corrupt in my application. I know how to convert the 308 (multiple by 1048576 = 322961408) part but I don't know what to do with the numbers after the decimal, it comes out as 849346.56 if I multiply it by 1048576. Any ideas on what I can do? I didn't see anything that would help in the API for Randomaccessfile.

**Eranga** · 10-27-2008, 04:46 AM

Use,

Java Code:

file.length();

on the file object. It gives the size of a file in bytes. Actually it gives the size of the file content, not the disk usage of the file.

**J-Live** · 10-27-2008, 04:56 AM

The file is on a server and I don't want the application to rely on just .getContentLength(). I would like to set it up so that if -1 is returned the user can input the size manually. Thank you for your response.

**Eranga** · 10-27-2008, 04:59 AM

So you want to find the file size on client side, where the file is on the server, is it?

**J-Live** · 10-27-2008, 05:05 AM

No, the files will be taken from sites like Megaupload, Deposit Files, Rapidshare, etc... They give the file size as: 90.53 MB for example. So, the user will be able to input that value. I want to convert that value to bytes.

**J-Live** · 10-27-2008, 08:24 AM

I guess I'll just round the result.

**Eranga** · 10-28-2008, 08:06 AM

So you are looking some mathematical explanation here.

Read this page.

**Norm** · 10-28-2008, 02:41 PM

If the file is on an HTTP server, you can use the HTTP HEAD request to get the size of the file. It will return the length in the response header field: Content-length: