Java get image extension from byte array

Question

I have the below code for saving an image from a byte array.

I am able to save the image successfully using the below code.

Currently I am saving image with

Answer 1

There are many solutions. Very simple for example:

String contentType = URLConnection.guessContentTypeFromStream(new ByteArrayInputStream(imageBytes));

Or you can use third-party libraries. Like Apache Tika:

String contentType = new Tika().detect(imageBytes);

Answer 2

Would you use the prefix header data:image/png;base64 of the base64 image data?

From the RFC, the "data" url definition:

### Form : `data:[<mediatype>][;base64],<data>`
### Syntax:
`dataurl   := "data:" [ mediatype ] [ ";base64" ] "," data
mediatype:= [ type "/" subtype ] *( ";" parameter )
data       := *urlchar
parameter  := attribute "=" value`

Samples:

data:image/gif;base64,R0lGODdhMAAwAPAAAAAAAP///ywAAAAAMAAw......

Then you can get the extension with gif.