ASP.NET Core反序列化PHP生成的JSON得到空.NET对象如何解决？

原始JSON样例 #

PHP生成的JSON数据结构如下：

[{
    "model": "XXXXX",
    "category": "Some Category",
    "description": "Hydrostatic",
    "id": "xyz123",
    "diagram": {
        "type": "Clutch",
        "name": "Clutch",
        "image": {
            "remote_url": "http://example.com/img/1565602310.png",
            "local_name": "diagram.png",
            "width": 919,
            "height": 668
        },
        "parts": [{
            "part": "010",
            "partNumber": "N22-45X",
            "partName": "Super clutch",
            "qty": 1,
            "ic": "",
            "weight": 1.848,
            "coords": {
                "xFrom": 552,
                "yFrom": 540,
                "xTo": 674,
                "yTo": 607
            }
        }]
    }
}]

原有实现代码 #

读取JSON代码 #

在ASP.NET 5.0 Core环境下可正常读取本地JSON文件内容：

string path = Path.Combine(Environment.WebRootPath, "data/data.json");
string strJson = System.IO.File.ReadAllText(path);

初始反序列化代码 #

以下代码执行后反序列化结果始终为空：

List<ModelData> md = JsonSerializer.Deserialize<List<ModelData>>(strJson);
List<ModelData> m_data = new List<ModelData>();

初始实体类定义 #

namespace ColemanData.Models
{
    public class ModelData
    {
        public string Model { get; set; }
        public string Category { get; set; }
        public string Description { get; set; }
        public string BookCD { get; set; }
        public Diagram Diagram { get; set; }
        public List<Part> Parts { get; set; }

    }

    public class Diagram
    {
        public string Type { get; set; }
        public string Name { get; set; }
        public DiagramImage Image { get; set; }
    }

    public class DiagramImage
    {
        public string RemoteUrl { get; set; }
        public float Width { get; set; }
        public float Height { get; set; }
        public string LocalName { get; set; }
    }

    public class Part
    {
        public string Label { get; set; }
        public string Number { get; set; }
        public string Name { get; set; }
        public int Quantity { get; set; }
        public string Ic { get; set; }
        public float Weight { get; set; }
        public Coordinates Coordinates { get; set; }
    }

    public class Coordinates
    {
        public float XStart { get; set; }
        public float YStart { get; set; }
        public float XEnd { get; set; }
        public float YEnd { get; set; }
    }
}

问题解决方法 #

修改两处即可正常反序列化得到预期对象：

1. 调整实体类的属性命名，使其与JSON中的键名完全匹配
2. 将系统自带的JsonSerializer.Deserialize替换为Newtonsoft.Json提供的JsonConvert.DeserializeObject方法，调整后代码为var data = JsonConvert.DeserializeObject<List<ModelData>>(strJson);

注意：由于原始JSON最外层为方括号包裹的数组结构，反序列化时必须指定List<ModelData>作为泛型类型，才能被解析器正确识别。

修改后的实体类定义如下：

public class Image
{
    public string remote_url { get; set; }
    public string local_name { get; set; }
    public int width { get; set; }
    public int height { get; set; }
}

public class Coords
{
    public int xFrom { get; set; }
    public int yFrom { get; set; }
    public int xTo { get; set; }
    public int yTo { get; set; }
}

public class Part
{
    public string part { get; set; }
    public string partNumber { get; set; }
    public string partName { get; set; }
    public int qty { get; set; }
    public string ic { get; set; }
    public string pin { get; set; }
    public string remarks { get; set; }
    public double lbs { get; set; }
    public Coords coords { get; set; }
}

public class Diagram
{
    public string type { get; set; }
    public string name { get; set; }
    public Image image { get; set; }
    public List<Part> parts { get; set; }
}

public class Root
{
    public string model { get; set; }
    public string category { get; set; }
    public string description { get; set; }
    public string id{ get; set; }
    public Diagram diagram { get; set; }
}

内容的提问来源于stack exchange，提问作者Subrata Sarkar