handler instanceof HandlerMethod 一直为false 是因为导错了包
应该导入:

import org.springframework.web.method.HandlerMethod;

   @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        // 从http请求头中取出token
        final String token = request.getHeader(JwtUtil.AUTH_HEADER_KEY);
        //如果不是映射到方法，直接通过
        if(!(handler instanceof HandlerMethod)){
            return true;
        }
        //如果是方法探测，直接通过
        if (HttpMethod.OPTIONS.equals(request.getMethod())) {
            response.setStatus(HttpServletResponse.SC_OK);
            return true;
        }
        //如果方法有JwtIgnore注解，直接通过
        HandlerMethod handlerMethod = (HandlerMethod) handler;
        Method method=handlerMethod.getMethod();
        if (method.isAnnotationPresent(JwtIgnore.class)) {
            JwtIgnore jwtIgnore = method.getAnnotation(JwtIgnore.class);
            if(jwtIgnore.value()){
                return true;
            }
        }
//        LocalAssert.isStringEmpty(token, "token为空，鉴权失败！");
        if (StringUtils.isEmpty(token)){
            throw new BaseException("token为空，鉴权失败！");
        }
        //验证，并获取token内部信息
        Claims claims = JwtUtil.parseJWT(token);
        String userToken = claims.getSubject();
        //将token放入本地缓存
        WebContextUtil.setUserToken(userToken);
        return true;
    }