重复序列化和反序列化创建重复项目 [英] Repeated serialization and deserialization creates duplicate items

问题描述

大家好，我有我的JSON serealization一个问题。我使用的是Json.NET包统一下：我在寻找做一个数据库，在我的应用程序编辑和存储通过wwwForm我的服务器和一个PHP文件上。我没有问题，建立并推动它于净。问题是，当我加载它，数据库在最后一个新条目。 Database类是这样的：

Hi everyone i have a problem with my json serealization. I'm using the Json.NET package under Unity: I'm searching to make a Database, editable on my application and stored on my server through wwwForm and a php file. I have no problem to create it and to push it on the net. The problem is, when i load it, the database has a new entry at the end. The Database Class is this:

public class Database   {
    public List<Army> armies { get; set;}

    public Database() {
        armies = new List<Army>();
        armies.Add (new Army());
    }
}

public class Army
{
    public string faction { get; set;}
    public List<Unit> army { get; set;}

    public Army()
    {
        faction = "RED";
        army = new List<Unit>();
        army.Add (new Unit());
    }
}

public class Unit
{
    public string name { get; set;}
    public float fissionTimer { get; set;}
    public float HP { get; set;}
    public int shield { get; set;}
    public float strenght { get; set;}
    public float movSpeed { get; set;}
    public float attackSpeed { get; set;}
    public float farmAggro { get; set;}
    public int criticPossibility { get; set;}
    public int armorPenetration { get; set;}
    public bool isContagious { get; set;}
    public int contagePossibility { get; set;}
    public string imgName {get;set;}

    public Unit()
    {
        name = "standard";
        fissionTimer = 8;
        HP = 100;
        shield = 0;
        strenght = 10;
        movSpeed = 5;
        attackSpeed = 0.1f;
        farmAggro = 0.1f;
        criticPossibility = 0;
        armorPenetration = 0;
        isContagious = false;
        contagePossibility = 0;
        imgName = "Red";
    } 

    public Unit(string _name, float _fissionTimer, float _HP, int _shield, float _strenght, float _movSpeed, float _attackSpeed, 
                float _farmAggro, int _criticPossibility, int _armorPen, bool _iscontagious, int _contagePos, string _imgName)
    {
        name = _name;
        fissionTimer = _fissionTimer;
        HP = _HP;
        shield = _shield;
        strenght = _strenght;
        movSpeed = _movSpeed;
        attackSpeed = _attackSpeed;
        farmAggro = _farmAggro;
        criticPossibility = _criticPossibility;
        armorPenetration = _armorPen;
        isContagious = _iscontagious;
        contagePossibility = _contagePos;
        imgName = _imgName;
    }
}

序列化和反序列化，我使用的2种方法：

to serialize and deserialize i use those 2 methods:

IEnumerator LoadFile()
{
    WWW www = new WWW(dbPath);

    yield return www;

    var _database = JsonConvert.DeserializeObject<Database> (www.text);

    db = _database;
    SendMessage ("loaded", SendMessageOptions.DontRequireReceiver);
}

IEnumerator SaveFile(Database db)
{
    WWWForm form = new WWWForm();
    string serialized = JsonConvert.SerializeObject (db);
    form.AddField("theDatabase", serialized);

    WWW www = new WWW(phpPath, form);

    yield return www;

    if (www.error == null)
        Debug.Log ("saved" + serialized);
    else
        Debug.LogError ("error saving database");
}

使用默认构造函数，序列化和反序列化的结果是这样的：

The result of using the default constructor, serialized and deserialized is this:

{
    "armies": [
        {
            "faction": "RED",
            "army": [
                {
                    "name": "standard",
                    "fissionTimer": 8,
                    "HP": 100,
                    "shield": 0,
                    "strenght": 10,
                    "movSpeed": 5,
                    "attackSpeed": 0.1,
                    "farmAggro": 0.1,
                    "criticPossibility": 0,
                    "armorPenetration": 0,
                    "isContagious": false,
                    "contagePossibility": 0,
                    "imgName": "Red"
                }
            ]
        },
        {
            "faction": "RED",
            "army": [
                {
                    "name": "standard",
                    "fissionTimer": 8,
                    "HP": 100,
                    "shield": 0,
                    "strenght": 10,
                    "movSpeed": 5,
                    "attackSpeed": 0.1,
                    "farmAggro": 0.1,
                    "criticPossibility": 0,
                    "armorPenetration": 0,
                    "isContagious": false,
                    "contagePossibility": 0,
                    "imgName": "Red"
                }
            ]
        }
    ]
}

有2军队和2个单位。我哪里做错了吗？在此先感谢

There are 2 armies and 2 units. Where i am doing wrong? Thanks in advance

推荐答案

这是发生的原因是由于两件事情的组合：

The reason this is happening is due to the combination of two things:

1. 您的类的构造函数自动添加默认项各自的名单。 Json.Net呼吁那些相同的构造反序列化过程来创建对象实例。


2. Json.Net的默认行为是反序列化过程重用（即加入）现有列表，而不是取代它们。

要解决这个问题，你可以改变你的代码，这样你的构造不会自动添加默认的项目到你的列表，也可以配置的Json .NET来取代反序列化的列表，而不是重用他们。后者由可以通过改变 ObjectCreationHandling 设置为替换，如下所示：

To fix this, you can either change your code such that your constructors do not automatically add default items to your lists, or you can configure Json.Net to replace the lists on deserialization rather than reusing them. The latter by can be done by changing the ObjectCreationHandling setting to Replace as shown below:

JsonSerializerSettings settings = new JsonSerializerSettings();
settings.ObjectCreationHandling = ObjectCreationHandling.Replace;

var database = JsonConvert.DeserializeObject<Database>(www.text, settings);

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