递归拼装Tree结构数据

    @Override
    public List<Map<String, Object>> queryListTree() {
        List<Map<String,Object>> treeList = new ArrayList<>();   //结果list
        List<Map<String,Object>> list = reportDao.queryListTree(new HashMap<>()); //查出所有数据list（避免多次连接数据库）
        for (Map<String, Object> report : list) {
            if("-1".equals(report.get("rptPid")+"")){ //根节点判断
                //userTree.remove(user);
                ArrayList<Map<String,Object>> newList = new ArrayList<>();//list遍历过程中不允许remove操作，所以新new一个list
                newList.addAll(list);
                newList.remove(report);//移除本次节点，减少递归次数
                Map<String,Object> userMap = TreeList(report,newList);//递归方法
                treeList.add(userMap);
            }
        }
        return treeList;
    }

    /**
     * 递归拼装子节点
    * @Title: TreeList
    * @param @param user
    * @param @param userTree
    * @param @return
    * @return Map<String,Object>
     */
    private Map<String,Object> TreeList(Map<String,Object> report,List<Map<String,Object>> newList) {
        List<Map<String,Object>> childreList = new ArrayList<>();//子节点list

        for(Map<String,Object> newReport : newList){
            if(report.get("id").equals(newReport.get("rptPid"))){//判断是否当前节点的子节点
                String level = newReport.get("rptLevel")+"";//0：文件夹 1：模板
                //userTree.remove(userC);
                if("1".equals(level)){ //叶子节点   -- 不用递归
                    childreList.add(newReport);
                    continue;
                }
                //新的list 模拟remove当前节点
                ArrayList<Map<String,Object>> newList2 = new ArrayList<>();
                newList2.addAll(newList);
                newList2.remove(newReport);
                //递归
                Map<String, Object> userL = TreeList(newReport, newList2);
                childreList.add(userL);
            }
        }
        if("0".equals(report.get("rptLevel")+"")){//父节点
            report.put("children", childreList);
            //解决父节点无孩子是图标显示为叶子问题
            if(childreList.isEmpty())
                report.put("state", "closed");
        }
        return report;
    }

数据