public class OpenHandlerInterceptor extends HandlerInterceptorAdapter {

    private static final Logger LOGGER = Logger.getLogger(OpenHandlerInterceptor.class);

    protected static final String APPLICATION_CHARSET="application/json; charset=utf-8";

    protected static final String UTF_8 = "UTF-8";
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        try {
            if(handler instanceof HandlerMethod){
                HandlerMethod handlerMethod = (HandlerMethod) handler;
                Method method = handlerMethod.getMethod();
                CheckParam checkParam = method.getAnnotation(CheckParam.class);
                if(checkParam == null || !checkParam.require() || StringUtils.isEmpty(checkParam.fieldNames())) {
                    return true;
                }
                //防止中文，符號
                String fieldNames = checkParam.fieldNames().replace("，",",");
                boolean jsonParam = CheckFieldsNotNull(request, fieldNames);
                if(!jsonParam){
                    ErrorMsg(response);
                    return false;
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
            ErrorMsg(response);
            return false;
        }
        return true;

    }

    /**
     * 校驗必傳引數屬性是否存在
     * @param request
     * @param fieldNames
     * @return
     * @throws Exception
     */
    public static boolean CheckFieldsNotNull(HttpServletRequest request, String fieldNames) throws Exception{
        LOGGER.info(String.format("校驗欄位：{%s}",fieldNames));
        String requestParam = HttpHelper.getBodyString(request);
        if(StringUtils.isEmpty(requestParam)){
            return false;
        }
        Gson gson = new Gson();
        ArrayList<Map> arrayList = gson.fromJson(requestParam, ArrayList.class);
        for (String fieldName : fieldNames.split(",")) {
            Preconditions.checkNotNull(arrayList.get(0).get(fieldName),fieldName + "is null");
        }
        return true;
    }

    /**
     * 錯誤資訊
     * @param response
     * @throws IOException
     */
    public static void ErrorMsg( HttpServletResponse response) throws Exception {
        PrintWriter out = response.getWriter();
        response.setCharacterEncoding(UTF_8);
        response.setContentType(APPLICATION_CHARSET);
        out.write(JsonMapper.toJsonString(Result.fail(ErrorMessageEnum.MISS_REQUEST_PARAM.getValue(),ErrorMessageEnum.MISS_REQUEST_PARAM.getDesc())));
    }
}