Change ContentType or CharacterEncoding in Java Filter ONLY IF ContentType === JSON

Question

I\'m trying to ensure that all JSON responses from a Jersey based java application have a UTF-8 character encoding parameter appended to their ContentType header.

So

Answer 1

Using this answer as reference the solution to your question is to re-encode the JSON text as shown here:

public void doFilter(...) {
    final CharResponseWrapper wrappedResponse =
            new CharResponseWrapper((HttpServletResponse) response);

    chain.doFilter(request, wrappedResponse);

    final String content = wrappedResponse.toString();

    final String type = wrappedResponse.getContentType();
    if (type != null && type.contains(MediaType.APPLICATION_JSON)) {
        // Re-encode the JSON response as UTF-8.
        response.setCharacterEncoding("UTF-8");
        final OutputStream out = response.getOutputStream();
        out.write(content.getBytes("UTF-8"));
        out.close();
    }
    else {
        // Otherwise just write it as-is.
        final PrintWriter out = response.getWriter();
        out.write(content);
        out.close();
    }
}