public ResultData queryMenuList() {　
　 // 获取所有数据List

    List<MenuVo> list = MenuDao.queryMenuList();

　　 // 通过list.stream()将List结构转成Tree结构并返回

    List<MenuVo> collection = list.stream()

            .filter(o -> StrUtil.equals("-1", o.getPIdString()))

            .peek(o -> o.setChildList(getChildList(o, list)))

            .collect(Collectors.toList());

    return ResultData.success(Constants.QUERY_SUCCESS, collection, collection.size());

}

// 递归方法

private List<MenuVo> getChildList(MenuVo MenuVo, List<MenuVo> list) {

    return list.stream()

            .filter(o -> StrUtil.equals(String.valueOf(MenuVo.getIdString()), o.getPIdString()))

            .peek(o -> o.setChildList(getChildList(o, list)))

            .collect(Collectors.toList());