How can I get MIME type of an InputStream of a file that is being uploaded?

Question

Simple question: how can I get MIME type (or content type) of an InputStream, without saving file, for a file that a user is uploading to my servlet?

Answer 1

I think this solves problem:

    public String readIt(InputStream is) {
    if (is != null) {
            BufferedReader reader = new BufferedReader(new InputStreamReader(is, "utf-8"), 8);

            StringBuilder sb = new StringBuilder();
            String line;
            while ((line = reader.readLine()) != null) {
                sb.append(line).append("\n");
            }
            is.close();
            return sb.toString();
    }
    return "error: ";
}        

What it returns? For example for png : "♦PNG\n\n♦♦♦.....", for xml:

Quite usefull, You cant try string.contains() to check what is it