apollo-portal/src/main/java/com/ctrip/framework/apollo/portal/spi/defaultimpl/DefaultLogoutHandler.java/DefaultLogoutHandler/logout
class DefaultLogoutHandler:  @Override
  public void logout(HttpServletRequest request, HttpServletResponse response) {
    try {
      response.sendRedirect("/");
    } catch (IOException e) {
      throw new RuntimeException(e);
    }
  }