apollo-adminservice/src/main/java/com/ctrip/framework/apollo/adminservice/filter/AdminServiceAuthenticationFilter.java/AdminServiceAuthenticationFilter/doFilter
class AdminServiceAuthenticationFilter:  @Override
  public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain)
      throws IOException, ServletException {
    if (bizConfig.isAdminServiceAccessControlEnabled()) {
      HttpServletRequest request = (HttpServletRequest) req;
      HttpServletResponse response = (HttpServletResponse) resp;

      String token = request.getHeader(HttpHeaders.AUTHORIZATION);

      if (!checkAccessToken(token)) {
        logger.warn("Invalid access token: {} for uri: {}", token, request.getRequestURI());
        response.sendError(HttpServletResponse.SC_UNAUTHORIZED, "Unauthorized");
        return;
      }
    }

    chain.doFilter(req, resp);
  }