Question

In a servlet I had to read an image file from disk, encode it to Base64 and then send back to the client. Because I only found samples for iOS, Python and some other kinds (principally all do it the same way) I thought I post my code here to help others 😉

CAUTION!
This should only work for files up to 2GB: setting capacity of ByteBuffer only takes an int.

Answer 1

Why so complicated and why read the complete image into memory?
A much simpler solution:

protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { 
    sun.misc.BASE64Encoder enc = new sun.misc.BASE64Encoder();
    enc.encode(new FileInputStream("/path/to/file.whatever"), response.getOutputStream());
}