java url encoder 的一个问题

    @RequestMapping(value = {"/search"})
    public String errorPath(HttpServletResponse response,
                            @RequestParam(value = "keyword") String keyword,
                            @RequestParam(value = "via") String via) throws IOException {
        response.setStatus(HttpServletResponse.SC_MOVED_PERMANENTLY);
        String url = "/search/"+ URLEncoder.encode(keyword, "UTF-8")+"/4";
        response.setHeader("Location", url);
        response.sendRedirect(url);
        return "";
    }