Java 實現樹結構計算各個節點數的和
阿新 • • 發佈:2022-04-06
private List<ESHomeSearchTreeVo> tree(List<ESHomeSearchTreeVo> allList){ // 構建的整個樹資料 List<TreeNode<String>> treeNodeList = allList.stream().map(x -> { Map<String, Object> extraMap = new HashMap<>(); extraMap.put("num", x.getNum());// 單個樹資料構建 TreeNode<String> treeNode = new TreeNode<String>() .setId(String.valueOf(x.getId())) // 主鍵 .setParentId(String.valueOf(x.getParentId())) // 父節點ID .setName(x.getName()) // 名稱 .setExtra(extraMap);return treeNode; }).collect(Collectors.toList()); // 配置 TreeNodeConfig treeNodeConfig = new TreeNodeConfig(); // 自定義屬性名(修改預設名稱) treeNodeConfig.setChildrenKey("children"); // 最大遞迴深度 treeNodeConfig.setDeep(10); //轉換器 List<Tree<String>> treeNodes = TreeUtil.build(treeNodeList, "0", treeNodeConfig, (treeNode, tree)-> { // 給樹節點賦值(還能set 父 或子節點樹) tree.setId(treeNode.getId()); tree.setParentId(treeNode.getParentId()); tree.setName(treeNode.getName()); tree.putExtra("num", treeNode.getExtra().getOrDefault("num", null)); }); treeNodes.forEach(this::warehouse); List<ESHomeSearchTreeVo> esHomeSearchTreeVos = JSONUtil.toList(JSONUtil.toJsonStr(treeNodes), ESHomeSearchTreeVo.class); return esHomeSearchTreeVos; }
計算每個節點的值
private void warehouse(Tree<String> e) { // 如果沒有子節點返回自己 if (e.getChildren() == null) { e.putExtra("num", e.get("num")); return; } // 有子節點的話進行相應處理 e.getChildren().forEach(this::warehouse); int num = e.getChildren().stream().mapToInt(m -> MapUtil.getInt(m, "num")).sum(); e.putExtra("num", num); }
結果: