Java-根据父级id将List结构转Tree结构

 List的stream

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());