Unityjson file creation and reading

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using LitJson;
using System.IO;
using System.Text.RegularExpressions;
using UnityEditor;
using System;

public class LevelJosnManager : MonoBehaviour
{


#if UNITY_EDITOR
   public static string  filepath = Application.streamingAssetsPath+"/LevelData.json";
#else

#endif
    /// <summary>
    ///  Store friend information 
    /// </summary>
    public static void SaveJson()
    {
        // because JsonMapper.ToJson Method does not support int convert to string type , So use this line of code to put int convert to string
        JsonMapper.RegisterImporter<int, string>((int value) =>
        {
            return value.ToString();
        });
        // Save the data as Json File format , Convert a data object to json Format string 
        string jsonData = JsonMapper.ToJson(ReadJson());

        // Create file operation 
        FileInfo fileInfo = new FileInfo(filepath);
        // establish json file 
        if (!fileInfo.Exists)
        {
            fileInfo.Create().Dispose();
            fileInfo.Refresh();
        }

        /// Using regular expressions   Garbled code json Turn into UTF-8
        Regex reg = new Regex(@"(?i)\\[uU]([0-9a-f]{4})");
        jsonData = reg.Replace(jsonData, delegate (Match m) { return ((char)Convert.ToInt32(m.Groups[1].Value, 16)).ToString(); });

        // Write content 
        StreamWriter write = new StreamWriter(filepath);
        write.WriteLine(jsonData);
        write.Dispose();
        write.Close();
#if UNITY_EDITOR
        // Refresh List View 
        AssetDatabase.Refresh();
#endif 
    }

    /// <summary>
    ///  Read json  file 
    /// </summary>
    public static List<Level> ReadJson()
    {
         // file does not exist 
        if (!File.Exists(filepath))
        {
            if (LevelList==null)
            {
                LevelList = new List<Level>();
            }
            return LevelList;
        }

        // Read json  file 
        StreamReader reader = new StreamReader(filepath);

        // without json File to create a 
        LevelList = 
            JsonMapper.ToObject<List<Level>>(reader.ReadToEnd()) ?? new List<Level>();
        reader.Dispose();
        reader.Close();
        return LevelList;
    }


    /// <summary>
    ///  Level list 
    /// </summary>
    public static List<Level> LevelList;



}

/// <summary>
///  The data of each level 
/// </summary>
public class Level
{
   public List<Box> boxList;
   public List<string> levelCarList;
}


public class Box
{
    /// <summary>
    ///  square ID
    /// </summary>
    public string boxID;

    /// <summary>
    ///  Grid type 
    /// </summary>
    public string boxLevelKing;

    /// <summary>
    ///  Grid direction 
    /// </summary>
    public string boxLevelDirection;


}