HTTP headers encoding/decoding in Java

Question

A custom HTTP header is being passed to a Servlet application for authentication purposes. The header value must be able to contain accents and other non-ASCII characters, so must be in a certain encoding (ideally UTF-8).

I am provided with this piece of Java code by the developers who control the authentication environment:

String firstName = request.getHeader("my-custom-header"); 
String decodedFirstName = new String(firstName.getBytes(),"UTF-8");

But this code doesn't look right to me: it presupposes the encoding of the header value, when it seemed to me that there was a proper way of specifying an encoding for header values (from MIME I believe).

Here is my question: what is the right way (tm) of dealing with custom header values that need to support a UTF-8 encoding:

• on the wire (how the header looks like over the wire)
• from the decoding point of view (how to decode it using the Java Servlet API, and can we assume that request.getHeader() already properly does the decoding)

Here is an environment independent code sample to treat headers as UTF-8 in case you can't change your service:

String valueAsISO = request.getHeader("my-custom-header"); 
String valueAsUTF8 = new String(firstName.getBytes("ISO8859-1"),"UTF-8");