How to identify file type by Base64 encoded string of a image

Question

I get a file which is Base64 encoded string as the image. But I think the content of this contains information about file type like png, jpeg, etc. How can I detect that? Is there any library which can help me here?

Answer 1

I have solved my problem with using mimeType = URLConnection.guessContentTypeFromStream(inputstream);

{ //Decode the Base64 encoded string into byte array
 // tokenize the data since the 64 encoded data look like this "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAoAAAAKAC"

    String delims="[,]";
    String[] parts = base64ImageString.split(delims);
    String imageString = parts[1];
    byte[] imageByteArray = Base64.decode(imageString );

    InputStream is = new ByteArrayInputStream(imageByteArray);

    //Find out image type
    String mimeType = null;
    String fileExtension = null;
    try {
        mimeType = URLConnection.guessContentTypeFromStream(is); //mimeType is something like "image/jpeg"
        String delimiter="[/]";
        String[] tokens = mimeType.split(delimiter);
        fileExtension = tokens[1];
    } catch (IOException ioException){

    }
}