c# 類實例序列化反序列化json文件 （原發佈 csdn 2017-10-01 20:02:12）

前言

前段時間使用了net.json保存對象數據。添加完成後，測試發現300多實例數據保存載入json文件，速度比原方式(BinaryFormatter)慢。但是功能加上後也懶再刪掉代碼了，索性就採用兩種方式。怎麼說兩種方式也比一種多不是？^_^

net.json詳細介紹

1 測試之前需要引用Newtonsoft.Json.dll，可在官網下載最新安裝包。本文寫作時最新Version 10.0.3

測試類Student

[JsonObject(MemberSerialization.Fields)]
class Student
{
    const int count = 1024;
    public Student(int ID, string Name, int Age, string Sex)
    {
        this.ID = ID;
        this.Name = Name;
        this.Age = Age;
        this.Sex = Sex;

        buffer = new byte[count];
        for (int i = 0; i < count; i++)
        {
            buffer[i] = (byte)i;
        }
    }
    
    byte[] buffer;

    int ID { get; set; }

    string Name { get; set; }

    int Age { get; set; }

    string Sex { get; set; }
    
    [JsonIgnore]
    IntPtr hwnd;

    [OnDeserialized]
    private void SetValuesOnDeserialized(StreamingContext context)
    {
        string stringA = "I seem to be turned around!";
        hwnd = System.Runtime.InteropServices.Marshal.StringToHGlobalAnsi(stringA);
    }
}

2 序列化對象預設情況下只有公共成員，此類沒有公共成員。故設置特性[JsonObject(MemberSerialization.Fields)]可序列化所有成員。詳細可見MemberSerialization

3 對於Intprt hwnd，標記為[JsonIgnore]表示不進行序列化；當進行反序列化後使用[OnDeserialized]可根據需要重新對其進行賦值 OnDeserializedAttribute 類，對於自定義序列化可參考msdn自定義序列化

測試用例

ArrayList StuModel = new ArrayList()
{
    new Student(1,"王小二",18,"男"),
    new Student(2,"麗麗",16,"女")
};

using (StreamWriter file = File.CreateText(@"test.json"))
{
    JsonSerializer serializer = new JsonSerializer();
    serializer.Serialize(file, StuModel);
}

using (StreamReader file = File.OpenText(@"test.json"))
{
    JsonSerializer serializer = new JsonSerializer();
    var movie2 = (ArrayList)serializer.Deserialize(file, typeof(ArrayList));
    for (int i = 0; i < movie2.Count; i++)
    {
        movie2[i] = JsonConvert.DeserializeObject<Student>(movie2[i].ToString());
    }
}

4 測試代碼中集合用ArrayList，故反序列化後需要再次進行轉換，把集合裡面的每個JObject轉換成Student，如果使用List就不需要，如下：

List<Student> StuModel = new List<Student>()
{
    new Student(1,"王小二",18,"男"),
    new Student(2,"麗麗",16,"女")
};

using (StreamWriter file = File.CreateText(@"test.json"))
{
    JsonSerializer serializer = new JsonSerializer();
    serializer.Serialize(file, StuModel);
}

using (StreamReader file = File.OpenText(@"test.json"))
{
    JsonSerializer serializer = new JsonSerializer();
    var movie2 = (List<Student>)serializer.Deserialize(file, typeof(List<Student>));
}