@Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws IOException {
        System.out.println("-----------------------進入攔截器-------------------------");
        //每次都會先發一個不帶引數的OPTIONS請求，若此請求失敗則不會發起正式請求，所以要過濾掉OPTIONS請求
        if (HttpMethod.OPTIONS.toString().equals(request.getMethod())) {
            System.out.println(
 
"OPTIONS請求，放行");
            return true;
        }
        try {
            String token=request.getHeader("Authorization");
            //如果驗證token失敗，並且方法註明了Authorization，返回401錯誤
            if (token == null) {

                //設定response狀態
                response.setStatus(HttpServletResponse.SC_UNAUTHORIZED);
                response.setCharacterEncoding(
 
"UTF-8");
                response.setContentType("application/json; charset=utf-8");

                //返回的資料
                JSONObject res = new JSONObject();
                res.put("status","-1");
                res.put("msg","need login");
                PrintWriter out = null ;
                out 
 
= response.getWriter();
                out.write(res.toString());
                out.flush();
                out.close();


                return false;
            }
        }catch (Exception e){
            return false;
        }

        return true;
    }