/** * OPTION requests are treated as CORS preflight requests * * @param req the original request * @param resp the response the answer are written to */ @Override protected void doOptions(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { Map<String, String> responseHeaders = requestHandler.handleCorsPreflightRequest( req.getHeader("Origin"), req.getHeader("Access-Control-Request-Headers")); for (Map.Entry<String, String> entry : responseHeaders.entrySet()) { resp.setHeader(entry.getKey(), entry.getValue()); } }