给定一个list，根据id和pid生成树结构

给定一个list，根据id和pid生成树结构

原始数据处理

//原始数据 
 List<ContractListingDetailinfoVO> list = contractListingDetailinfoDao.queryListingsDetailListByListingId(params);
//根数据
List<ContractListingDetailinfoVO> roots = list.stream().filter(o -> o.getPid() == null).collect(Collectors.toList());

            if (CollectionUtil.isNotEmpty(roots)){
                //除去根数据  减少数据处理
                list.removeAll(roots);
                //拼成树的结构
                this.fillTree(roots,list);
            }
//roots就是生成的树结构

递归处理 生成tree

 /**
     * //拼成树的结构
     * @param roots
     * @param list
     */
    /**
     * 根据根节点，去遍历子节点。获取最终tree结构
     *
     */
    private void fillTree(List<ContractListingDetailinfoVO> rootOrgDateList, List<ContractListingDetailinfoVO> orgDateDtoVoList) {
        for (ContractListingDetailinfoVO orgDtoVo : rootOrgDateList) {
            //获取父节点的子集
            List<ContractListingDetailinfoVO> children = fillChildren(orgDtoVo, orgDateDtoVoList);
            if (CollectionUtils.isEmpty(children)) {
                continue;
            }
            //子集不为空的话  递归  继续往下遍历
            orgDateDtoVoList.removeAll(children);
            fillTree(children, orgDateDtoVoList);
        }

    }

    /**
     * 根据父节点id，去遍历子节点（parentId），将子节点的结果set到父节点的Children。获取最终tree结构
     *
     */
    private List<ContractListingDetailinfoVO> fillChildren(ContractListingDetailinfoVO parent, List<ContractListingDetailinfoVO> orgDateDtoVoList) {
        List<ContractListingDetailinfoVO> childrenList = new ArrayList<>();
        for (ContractListingDetailinfoVO dtoVo : orgDateDtoVoList) {
            if (parent.getId().equals(dtoVo.getPid())) {
                childrenList.add(dtoVo);
                if (parent.getChild() == null) {
                    parent.setChild(new ArrayList<ContractListingDetailinfoVO>());
                }
                parent.getChild().add(dtoVo);
            }
        }
        return childrenList;
    }