.NET Core中如何将带路径键的扁平JSON转换为层级JSON对象

在.NET Core环境中，数据库存储的JSON Schema字符串为扁平结构，所有键以点分隔的路径形式存在。使用JObject.Parse解析后无法得到期望的嵌套层级JSON结构，需要将这类扁平JSON转换为嵌套结构返回给前端。

示例代码 #

string json = $@"{{
            ""xcollapse.id"":""xcollapse"",
            ""xcollapse.el"":202,
            ""xcollapse.cols.props.cn"":""title"",
            ""xcollapse.cols.props.desc"":"""",
            ""xcollapse.cols.props.visible"":-1,
            ""xcollapse.cols.children.id"":""f272681"",
            ""xcollapse.cols.children.el"":200,
            ""xcollapse.cols.children.props"":""{{}}""
        }}";

var jObj = JObject.Parse(json);

var result = jObj.ToString();

期望转换结果 #

{
  "xcollapse": {
    "id": "xcollapse",
    "el": 202,
    "cols": [
      {
        "props": {
          "cn": "title",
          "desc": "",
          "visible": -1
        },
        "children": {
          "id": "f272681",
          "el": 200,
          "props": {}
        }
      }
    ]
  }
}

数据库完整扁平JSON结构 #

{
    "xcollapse.id":"xcollapse",
    "xcollapse.el":202,
    "xcollapse.props":{},
    "xcollapse.styles.visible":-1,
    "xcollapse.cols.deletable":false,
    "xcollapse.cols.props.cn":"title",
    "xcollapse.cols.props.desc":"",
    "xcollapse.cols.props.visible":-1,
    "xcollapse.cols.styles":null,
    "xcollapse.cols.children.id":"f272681",
    "xcollapse.cols.children.el":200,
    "xcollapse.cols.children.props":{},
    "xcollapse.cols.children.styles.visible":-1,
    "xcollapse.cols.children.cols.deletable":false,
    "xcollapse.cols.children.cols.props.visible":-1,
    "xcollapse.cols.children.cols.styles.span":8,
    "xcollapse.cols.children.cols.children.id":"fname",
    "xcollapse.cols.children.cols.children.el":100,
    "xcollapse.cols.children.cols.children.props.ek":"fbillhead",
    "xcollapse.cols.children.cols.children.props.cn":"title",
    "xcollapse.cols.children.cols.children.props.group":"",
    "xcollapse.cols.children.cols.children.props.fn":"fname",
    "xcollapse.cols.children.cols.children.props.pn":"fname",
    "xcollapse.cols.children.cols.children.props.desc":"",
    "xcollapse.cols.children.cols.children.props.must":"0",
    "xcollapse.cols.children.cols.children.props.visible":-1,
    "xcollapse.cols.children.cols.children.props.len":"100",
    "xcollapse.cols.children.cols.children.props.lock":"0",
    "xcollapse.cols.children.cols.children.props.copy":"1",
    "xcollapse.cols.children.cols.children.props.defval":"",
    "xcollapse.cols.children.cols.children.props.canchange":"0",
    "xcollapse.cols.children.cols.children.props.xlsin":"1",
    "xcollapse.cols.children.cols.children.props.acl":"1",
    "xcollapse.cols.children.cols.children.props.sbm":"0",
    "xcollapse.cols.children.cols.children.props.notrace":"1",
    "xcollapse.cols.children.cols.children.props.apipn":"sourceType",
    "xcollapse.cols.children.cols.children.props.ctlfk":"",
    "xcollapse.cols.children.cols.children.props.editmode":"0",
    "xcollapse.cols.children.cols.children.props.xsslv":"0",
    "xcollapse.cols.children.cols.children.styles.align":"left",
    "xcollapse.cols.children.cols.children.styles.width":"",
    "xcollapse.cols.children.cols.children.styles.row":2,
    "xcollapse.cols.children.cols.children.cols":{},
    "xcollapse.cols.children.cols.children.deletable":true,
    "xcollapse.cols.children.cols.children.pid":"",
    "xcollapse.cols.children.cols.children.seq":1,
    "xcollapse.cols.children.cols.seq":1,
    "xcollapse.cols.children.deletable":true,
    "xcollapse.cols.children.pid":"",
    "xcollapse.cols.children.seq":1,
    "xcollapse.cols.seq":1,
    "xcollapse.deletable":true,
    "xcollapse.pid":"",
    "xcollapse.seq":1
}

实现工具方法遍历扁平JObject的键值对，拆分点分隔路径并递归构建嵌套结构，同时识别cols这类需要转为数组的节点（可根据需求扩展识别规则）。

using Newtonsoft.Json.Linq;

public static class JsonFlattenHelper
{
    public static JObject Unflatten(JObject flatJson)
    {
        var result = new JObject();

        foreach (var kvp in flatJson)
        {
            var pathSegments = kvp.Key.Split('.');
            JToken current = result;

            for (int i = 0; i < pathSegments.Length; i++)
            {
                var segment = pathSegments[i];
                bool isLastSegment = i == pathSegments.Length - 1;

                // 处理需要转为数组的节点（此处约定cols为数组节点）
                if (segment == "cols" && !isLastSegment)
                {
                    if (current[segment] == null)
                    {
                        current[segment] = new JArray();
                    }
                    var array = (JArray)current[segment];
                    // 扁平结构中cols子属性对应数组首个元素
                    if (array.Count == 0)
                    {
                        array.Add(new JObject());
                    }
                    current = array[0];
                }
                else
                {
                    // 处理普通对象节点
                    if (current[segment] == null)
                    {
                        current[segment] = isLastSegment ? kvp.Value : new JObject();
                    }
                    else if (!isLastSegment && current[segment].Type != JTokenType.Object)
                    {
                        // 冲突时替换为对象节点
                        current[segment] = new JObject();
                    }
                    current = current[segment];
                }
            }
        }

        return result;
    }
}

使用示例 #

string json = $@"{{
            ""xcollapse.id"":""xcollapse"",
            ""xcollapse.el"":202,
            ""xcollapse.cols.props.cn"":""title"",
            ""xcollapse.cols.props.desc"":"""",
            ""xcollapse.cols.props.visible"":-1,
            ""xcollapse.cols.children.id"":""f272681"",
            ""xcollapse.cols.children.el"":200,
            ""xcollapse.cols.children.props"":""{{}}""
        }}";

var flatJObj = JObject.Parse(json);
var nestedJObj = JsonFlattenHelper.Unflatten(flatJObj);

Console.WriteLine(nestedJObj.ToString(Newtonsoft.Json.Formatting.Indented));

运行后输出与期望结构一致，也能正确处理数据库中的完整扁平JSON，构建多层嵌套的层级结构。

内容的提问来源于stack exchange，提问作者beiduoan