private String inferMimeType(ServletRequest request) {
      String path = ((HttpServletRequest) request).getRequestURI();
      ServletContext context = config.getServletContext();
      return context.getMimeType(path);
    }
Infer the mime type for the response based on the extension of the request URI. Returns null
if unknown.
hbase-http/src/main/java/org/apache/hadoop/hbase/http/HttpServer.java