java-将DirectoryObject转换为用户

给定一个特定目录角色成员的查询,我想返回一个相应用户的列表.我所拥有的是：

IDirectoryObjectCollectionWithReferencesRequest request = graphServiceClient.directoryRoles(roleId).members().buildRequest();
IDirectoryObjectCollectionWithReferencesPage page = request.select(USER_FIELDS_TO_RETURN).get();
List<DirectoryObject> objects = page.getCurrentPage();
IDirectoryObjectCollectionWithReferencesRequestBuilder builder = page.getNextPage();
while (builder != null) {
    request = builder.buildRequest();
    page = request.select(USER_FIELDS_TO_RETURN).get();
    objects.addAll(page.getCurrentPage());
    builder = page.getNextPage();
}
return objects.stream().filter(o -> o.oDataType.equals("#microsoft.graph.user")).map(o -> new User()).collect(Collectors.toList());

问题在于return语句.仅对用户对象进行过滤(与比较oDataType相比,找不到比这更优雅的方法),并返回带有o内容的用户对象：

objects.stream().filter(o -> o.oDataType.equals("#microsoft.graph.user")).map(o -> {
        // the only thing that I could think of is to do some weird
        // serialization/deserialization logic here which is a bad solution
        // for anything other than a small number of elements
}).collect(Collectors.toList());

将DirectoryObject转换为User的正确方法是什么