NetworkSetting.json

[{"serverIP":"192.168.1.10","serverPort":"3000"}]

SocketSettings.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using LitJson;
using System.IO;

public class NetworkSetting{
    public string serverIP;
    public string serverPort;
    public NetworkSetting(string _serverIp, string _serverPort){
        serverIP = _serverIp;
        serverPort = _serverPort;
    }
}
public class SocketSettings : MonoBehaviour
{   
    public string ipAddress;
    public string port;
    public List<NetworkSetting> networkSettingList = new List<NetworkSetting>();
    private string networkSettingFile = "NetworkSetting.json";

    #region Save / Load Settings.
    public void LoadFromJson(){
        string filePath = Path.Combine(Application.streamingAssetsPath, networkSettingFile);
        string networkSettingJsonFile = File.ReadAllText(filePath);
        JsonData networkSettingJson = JsonMapper.ToObject(networkSettingJsonFile);
        // Assign them with class variables.
        ipAddress = networkSettingJson[0]["serverIP"].ToString();
        port = networkSettingJson[0]["serverPort"].ToString();
    }
    public void SaveToJson(){
        // Put them in the list, and make it Json data.
        networkSettingList.Add(new NetworkSetting(ipAddress,port));
        JsonData networkSettingJson = JsonMapper.ToJson(networkSettingList);
        networkSettingList.Clear();
        // Save Json to File
        string filePath = Path.Combine(Application.streamingAssetsPath, networkSettingFile);
        File.WriteAllText(filePath,networkSettingJson.ToString());
    }
    #endregion
}