java如何实现树形查询

@Query(value = "select * from TB_UIM_MENU_TEST t START WITH t.PID IS NULL" +
        " CONNECT BY PRIOR t.ID = t.PID order by t.PID NULLS first,t.MENU_SORT ASC",nativeQuery = true)
List<MenuTestDTO> findTree();

public List findTree() {
    List<MenuTreeVO> list = new ArrayList<>();
    List<MenuTestDTO> dataList = menuTestDAO.findTree();
    List<MenuTreeVO> resultList = new ArrayList<>();
    for (int i = 0; i < dataList.size(); i++) {
        MenuTestDTO menuTestDTO = dataList.get(i);
        MenuTreeVO menuTreeVO = new MenuTreeVO();
        menuTreeVO.setId(menuTestDTO.getId());
        menuTreeVO.setPid(menuTestDTO.getPid());
        menuTreeVO.setLockState(menuTestDTO.getLockState());
        menuTreeVO.setLogo(menuTestDTO.getLogo());
        menuTreeVO.setMenuSort(menuTestDTO.getMenuSort());
        menuTreeVO.setName(menuTestDTO.getName());
        menuTreeVO.setRoute(menuTestDTO.getMenuRoute());
        resultList.add(menuTreeVO);
    }
    for (int i = 0; i < resultList.size(); i++) {
        MenuTreeVO menuTreeVO = resultList.get(i);
        if (menuTreeVO.getPid() == null){
            //一级节点
            list.add(menuTreeVO);
        }else {
            //子节点
            findFather(menuTreeVO,list);
        }
    }
    return list;
}

private List findFather(MenuTreeVO private List findFather(MenuTreeVO menuTreeVO,List list){
    for (int i = 0; i < list.size(); i++) {
        MenuTreeVO menuvo = list.get(i);
        //判断是否为对应节点的子节点
        if (menuvo.getId().equals(menuTreeVO.getPid())){
            menuvo.getChildren().add(menuTreeVO);
        }
    }
    return null;
}

private List<MenuTreeVO> children = new ArrayList<>();