JSON相關(guān)

json是國際通用語言，可以跨平臺(tái)（游戲，軟件，網(wǎng)頁，不同OS）使用，

json語法較為簡單，使用更廣泛。json使用鍵值對(duì)來存儲(chǔ)。

認(rèn)識(shí)json文件

//注意字典類型存儲(chǔ)時(shí)，鍵是以string類型存儲(chǔ)的 需要添加“”

{
  "name": "TonyChang",
  "age":21,
  "sex":true,
  "Float": 2.5,
  "arrarys":[1,5,9],
  "friends": [{"name": "Tom","age":21, "sex":true,"Float": 2.8},
    {"name": "Peter","age":17, "sex":true,"Float": 3.5},
    {"name": "Jack","age":25, "sex":true,"Float": 5.0}
  ],
  "university": {"address": "唐山","province":"河北"},
  "dic": {"1":"125","2": 911}, 
  "son": null
}

Excel轉(zhuǎn)換為JSON文件：

使用網(wǎng)站來轉(zhuǎn)換：bejson

挖坑-----》開發(fā)一個(gè)工具，使各種類型存儲(chǔ)文件進(jìn)行轉(zhuǎn)換。

Json的讀寫：

1. jsonUtlity中的使用：

   string jisonStr = JsonUtility.ToJson(_writer);
   File.WriteAllText(Application.persistentDataPath+"/DemoJson1.json",jisonStr);
   

   轉(zhuǎn)儲(chǔ)為JSON時(shí)要點(diǎn)：

   1. float存儲(chǔ)時(shí)看起來會(huì)有一些誤差
   2. 自定義類序列化要添加序列化特性[System.Serializable]
   3. 想要序列化私有變量，需要添加序列化特性[SerializeField]
   4. JsonUtility不支持字典
   5. JsonUtility存儲(chǔ)對(duì)象時(shí)候不會(huì)為null是默認(rèn)值的數(shù)值

完整的類

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

namespace Building.JSON
{
    public class Writer
    {
        public string name;
        public int age;
        public bool sex;
        [SerializeField]
        protected float numberF = 3.15f;
        [SerializeField]
        private double numberD = 6.15;
        public List<int> Array;
        public IDCard idcard;
    }

    [Serializable]
    public class IDCard
    {
        public int stu_id;
        public int cl_id;
    }
    public class JsonPractice:MonoBehaviour
    {
        private Writer _writer;

        private void Awake()
        {
            _writer = new Writer();
            _writer.name = "TonyCode";
            _writer.sex = true;
            _writer.age = 21;
            _writer.Array = new List<int>() {1, 2, 3, 4, 5};
            _writer.idcard = new IDCard();
            _writer.idcard.cl_id = 256;
            _writer.idcard.cl_id = 206;
            string jisonStr = JsonUtility.ToJson(_writer);
            File.WriteAllText(Application.persistentDataPath+"/DemoJson1.json",jisonStr);
            print(Application.persistentDataPath);
        }
    }
}

存儲(chǔ)生成的json文件內(nèi)容。

反序列化:

string jsonStrRead = File.ReadAllText(Application.persistentDataPath + "/DemoJson1.json");
//反序列化 
Writer writer01 = JsonUtility.FromJson<Writer>(jsonStrRead);
Writer writer02=JsonUtility.FromJson(jsonStrRead,typeof(Writer)) as Writer;

注意：使用JsonUtility.FromJson進(jìn)行反序列化時(shí)候接受對(duì)象是一個(gè)對(duì)象，不能是一個(gè)數(shù)據(jù)集合來接受Json中存儲(chǔ)的數(shù)據(jù)內(nèi)容。并且json的編碼格式必須為UTF-8。

JSON文件的寫入與讀取，本質(zhì)是對(duì)text文本的讀寫，所以會(huì)調(diào)用File類中對(duì)text文本相關(guān)的方法。

先將類轉(zhuǎn)換為string字符串（Json文件格式的字符串），然后調(diào)用文件方法進(jìn)行讀寫。

2.LitJson（第三方開發(fā)的工具包）

 //使用LitJson存儲(chǔ)
 string jsonStr2=JsonMapper.ToJson(_writer);
 File.WriteAllText(Application.persistentDataPath+"/DemoJson2.json",jsonStr);

注意：（區(qū)別JsonUtility）

• 不能序列化private變量；
• 對(duì)于自定義類不需要添加序列化特性就可以進(jìn)行序列化；
• 支持字典類型，建議字典類型的鍵的類型為“string”；
• 可以準(zhǔn)確保存null類型；

//使用LitJson讀（反序列化）
string jsonStrRead3 = File.ReadAllText(Application.persistentDataPath + "/DemoJson2.json");
//方法一
JsonData data = JsonMapper.ToObject(jsonStrRead3);
print(data["name"]);
//方法二 （使用較多）
Writer writer03= JsonMapper.ToObject<Writer>(jsonStrRead3);

讀取數(shù)據(jù)集合：

//數(shù)據(jù)集合中元素類型
public class RoleInfo
{
    public int hp;
    public int speed;
    public int volume;
    public string resName;
    public int scale;
}
//讀取數(shù)據(jù)集合
 string jsonStrRoleList = File.ReadAllText(Application.persistentDataPath + "/RoleInfo.json");
 List<RoleInfo> roleInfos = JsonMapper.ToObject<List<RoleInfo>>(jsonStrRoleList);
 foreach (var roleInfo in roleInfos )
 {
 	print(roleInfo.hp+"   "+roleInfo.speed+"   "+roleInfo.resName);
 }

RoleInfo.json內(nèi)容

[
{"hp":4,"speed":6,"volume":5,"resName":"Airplane/Airplane1","scale":15},
{"hp":3,"speed":7,"volume":4,"resName":"Airplane/Airplane2","scale":15},
{"hp":2,"speed":8,"volume":3,"resName":"Airplane/Airplane3","scale":15},
{"hp":10,"speed":3,"volume":10,"resName":"Airplane/Airplane4","scale":6},
{"hp":6,"speed":5,"volume":7,"resName":"Airplane/Airplane5","scale":10}
]

讀取字典：

 //讀取字典
 //注意字典元素內(nèi)容最后一個(gè)不應(yīng)當(dāng)添加逗號(hào)
 string jsonStrDic = File.ReadAllText(Application.persistentDataPath + "/JsonDic.json");
 Dictionary<string, int> games = JsonMapper.ToObject<Dictionary<string, int>>(jsonStrDic);
 foreach (KeyValuePair<string,int> kv in games)
 {
	 print(kv.Key+" "+kv.Value);
 }

JsonDic.json中內(nèi)容：

{
   "Tony": 100,
   "Jack": 125,
   "Pony": 156,
   "Tom": 126
}

注意：

1. litJson支持字典存儲(chǔ)，字典鍵的類型為string
2. 自定義類結(jié)構(gòu)一定要有無參構(gòu)造函數(shù)
3. LitJson可以直接讀取數(shù)據(jù)集合
4. LitJson讀取字典元素時(shí)候 字典內(nèi)容最后一個(gè)不可以加逗號(hào)（可能反序列化失?。?/strong>

using System.IO;
using LitJson;
using UnityEngine;

namespace Building.JSON
{
    public enum SaveJsonType
    {
        JsonUtility,
        LitJson
    }
    public class JsonManager
    {
        private static JsonManager instance=new JsonManager();
        public static JsonManager Instance => instance;

        private JsonManager()
        {
            
        }
        /// <summary>
        ///  存儲(chǔ)Json方法
        /// </summary>
        /// <param name="data">要存儲(chǔ)的數(shù)據(jù)類</param>
        /// <param name="FileName">存儲(chǔ)文件名稱</param>
        /// <param name="type">存儲(chǔ)方法</param>
        public void SaveJson(object data, string FileName,SaveJsonType type=SaveJsonType.LitJson)
        {
            //確定路徑
            string path = Application.persistentDataPath + "/"+FileName+ ".json";
            string jsonStr="";
            switch (type)
            {
                case SaveJsonType.LitJson:
                    jsonStr = JsonMapper.ToJson(data);
                    break;
                case SaveJsonType.JsonUtility:
                    jsonStr = JsonUtility.ToJson(data);
                    break;
            }
           //寫入文件
           File.WriteAllText(path,jsonStr);
        }
        
        /// <summary>
        /// 讀取json方法
        /// </summary>
        /// <param name="FileName">讀取json的名稱</param>
        /// <param name="type">讀取方式</param>
        /// <typeparam name="T">讀取json文件中數(shù)據(jù)類型</typeparam>
        /// <returns></returns>
        public T LoadJson<T>(string FileName, SaveJsonType type = SaveJsonType.LitJson) where T : new()
        {
            //確定路徑
            string path = Application.persistentDataPath + "/"+FileName+ ".json";
            if (!File.Exists(path))
            {
                path=Application.streamingAssetsPath+"/"+FileName+".json";
                if (!File.Exists(path))
                {
                    return new T();
                }
            }
            string jsonStrRead=File.ReadAllText(path);
            T data = default(T);
            switch (type)
            {
                case SaveJsonType.LitJson:
                    data=JsonMapper.ToObject<T>(jsonStrRead);
                    break;
                case SaveJsonType.JsonUtility:
                    data= JsonUtility.FromJson<T>(jsonStrRead);
                    break;
            }
            return data;
        }
    }
}