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

It depends on where you are getting the input stream from. If you are getting it from a servlet then it is accessable through the HttpServerRequest object that is an argument of doPost. If you are using some sort of rest API like Jersey then the request can be injected by using @Context. If you are uploading the file through a socket it will be your responsibility to specify the MIME type as part of your protocol as you will not inherit the http headers.