Unity读写Json文件的两种方式

本篇介绍在Unity中读写Json文件的两种方式：1.JsonUtility；2.LitJson；

注意：在使用LitJson前需要先将文件拖入unity项目中

一、JsonUtility与LitJson的区别

1.JsonUtility使用自定义类需要加特性，而LitJson不需要

2.JsonUtility支持私有和保护变量，而LitJson不支持

3.JsonUtility不支持字典，而LitJson支持，但是当字典在序列化时如果键含int等非string类型，反序列化时会读取不到，因为序列化后非string类型的键可以理解为已经被改为string类型（但事实不是，没改，但可以当做去理解，想搞清原因可以自己去查一下）

4.JsonUtility不能直接将数组反序列化，而LitJson可以，比如{ {1,2}，{3,4}}

5.LitJson需要无参构造，但JsonUtility不需要

6.LitJson存储null时存储的就是null，但JsonUtility存储的是默认值

二、JsonUtility的使用

2.1读取json

  string jsonstr2=File.ReadAllText(Application.persistentDataPath + "/" + "testJson.json");
  Debug.Log(jsonstr2);
  PlayerInfo playerInfo=new PlayerInfo(); 
  playerInfo=JsonUtility.FromJson<PlayerInfo>(jsonstr2);

2.2写入json

[Serializable]
public class Message
{
    public int id;
    public int num;
    public Message(int id,int num)
    {
        this.id = id;
        this.num = num;
    }
}
public class Cherry
{
    public string name;
    public int atk;
    public int def;
    public float movespeed;
    public double roundspeed;
    public Message weapon;
    public List<int> listInt;
    public List<Message> itemList;
    [SerializeField]
    private int privateI = 1;
    [SerializeField]
    protected int protectedI = 2;
}
public class JsonUtilityTest: MonoBehaviour
{
    
    void Start()
    {
        Cherry cherry=new Cherry();
        cherry.name = "Cherry";
        cherry.atk = 10;
        cherry.def = 5;
        cherry.movespeed = 20.5f;
        cherry.roundspeed = 21.4f;
        cherry.weapon = new Message(1, 1);
        cherry.listInt = new List<int>() { 1, 2, 3, 4, 5 };
        cherry.itemList = new List<Message>() { new Message(1,99),new Message(2,44)};

        SaveData(cherry);
    }

    public void SaveData(Cherry cherry)
    {
        string jsonStr=JsonUtility.ToJson(cherry);
        Debug.Log(Application.persistentDataPath);
        File.WriteAllText(Application.persistentDataPath + "/" +                                 
        "testJson.json",jsonStr);
    }


}

三、LitJson的使用

3.1.读取json

private void ReadJson()
{
    string readjsondata = File.ReadAllText(Application.persistentDataPath+"/"+"Cherry2.json");
    Cherry cherry2 = JsonMapper.ToObject<Cherry>(readjsondata);
    Debug.Log(readjsondata);
}

3.2写入json

using LitJson;
public class Student2
{
    public int age;
    public string name;
    public Student2(){}
    public Student2(int age,string name)
    {
        this.age = age;
        this.name = name;
    }
}
public class Cherry
{
    public string name;
    public int age;
    public bool Sex;
    public float testF;
    public double testD;

    public int[] ids;
    public List<int> ids2;
    //public Dictionary<int, string> dic;
    public Dictionary<string, string> dic2;
    public Student2 s1;
    public List<Student2> s2s;
    private int privateI = 1;
    protected int protectedI = 2;
}

public class LitJsonTest : MonoBehaviour
{
    // Start is called before the first frame update
    void Start()
    {
        Cherry cherry = new Cherry();
        cherry.name = "cherry";
        cherry.age = 24;
        cherry.Sex = false;
        cherry.testF = 1.2f;
        cherry.testD = 1.3d;
        cherry.ids=new int[] {1,2,3,4};
        cherry.ids2 = new List<int> { 5,6,7,8};
        //cherry.dic=new Dictionary<int, string>() { { 1, "2, 3, 4" } };
        cherry.dic2 = new Dictionary<string, string>() { { "1","123"},{ "2","234"} };
        cherry.s1 = new Student2(1,"yan");
        cherry.s2s = new List<Student2>() { new Student2(2, "啊"), new Student2(3, "haha") };

        SendJson(cherry);
        ReadJson();
    }

    private void SendJson(Cherry cherry)
    {
        string jsondata = JsonMapper.ToJson(cherry);
        Debug.Log(jsondata);
        File.WriteAllText(Application.persistentDataPath + "/" + "Cherry2.json", jsondata);
        Debug.Log(Application.persistentDataPath);
    }
}