ASP.NET读取JSON文件映射实体类无值问题求助

我有一个酒店预订JSON文件，已经创建了对应的实体类，想要把JSON数据保存到类的属性中，但当前编写的读取代码无法获取到任何值，求指导如何正确读取所有JSON节点并完成数据映射。

JSON内容 #

{"header": {"hid": "95845-5bhj-j908-o987-hhg5665","datestamp": "2024-01-21"},"body": [{"hotelbooking": [{"Customer": {"Bookings": {"Profile": {"name": "Test","dob": "1989-01-01","mobile": "+919999999999","address": "C-366,Saket,Delhi,INDIA,110044","email": "test@gmail.com","id": "GH2673677"},"roomtype": "DELUXE POOL VIEW"}},"BookingStatus": {"Confirm": {"amount": 4800},"Pax": "4","currency": "THB","bookDateTime": "2024-01-21T21:10:54Z","address": "PATONG","days": "4","paymentstatus": "CONFIRM"},"RoomDetails": {"Rooms": [{"roomtype": "DELUXE GARDEN VIEW","pricepernight": 1000,"currency": "THB","refid": "0032514569"},{"roomtype": "DELUXE POOL VIEW","pricepernight": 1200,"currency": "THB","refid": "0069584214"},{"roomtype": "DELUXE SEA VIEW","pricepernight": 1300,"currency": "THB","refid": "0098541239"},{"roomtype": "SUITE POOL VIEW","pricepernight": 2000,"currency": "THB","refid": "0036521456"},{"roomtype": "SUITE POOL ACCESS","pricepernight": 3000,"currency": "THB","refid": "002651425"},{"roomtype": "PRESEDENTIAL SUITE INFINITY POOL","pricepernight": 6000,"currency": "THB","refid": "006985321"}],"bookstartDate": "2024-04-09","bookendDate": "2024-04-13"},"paymentmode": "cc","creditcardNumber": "XXXXXXXXXXXX8976","paymentRef": "bhgd73838-jdf73738"}],"customerId": "yryu78876","paymentbank": "DBS Bank","secdeposit": "No","OtherInfo": [{"ExtraBed": "No","Breakfast": "Yes","RefNo": "0069584214"}]}]}

实体类代码 #

public class Body
{
    public List<Hotelbooking> hotelbooking { get; set; }
    public string customerId { get; set; }
    public string paymentbank { get; set; }
    public string secdeposit { get; set; }
    public List<OtherInfo> OtherInfo { get; set; }
}

public class Bookings
{
    public Profile Profile { get; set; }
    public string roomtype { get; set; }
}

public class BookingStatus
{
    public Confirm Confirm { get; set; }
    public string Pax { get; set; }
    public string currency { get; set; }
    public DateTime bookDateTime { get; set; }
    public string address { get; set; }
    public string days { get; set; }
    public string paymentstatus { get; set; }
}

public class Confirm
{
    public int amount { get; set; }
}

public class Customer
{
    public Bookings Bookings { get; set; }
}

public class Header
{
    public string hid { get; set; }
    public string datestamp { get; set; }
}

public class Hotelbooking
{
    public Customer Customer { get; set; }
    public BookingStatus BookingStatus { get; set; }
    public RoomDetails RoomDetails { get; set; }
    public string paymentmode { get; set; }
    public string creditcardNumber { get; set; }
    public string paymentRef { get; set; }
}

public class OtherInfo
{
    public string ExtraBed { get; set; }
    public string Breakfast { get; set; }
    public string RefNo { get; set; }
}

public class Profile
{
    public string name { get; set; }
    public string dob { get; set; }
    public string mobile { get; set; }
    public string address { get; set; }
    public string email { get; set; }
    public string id { get; set; }
}

public class Room
{
    public string roomtype { get; set; }
    public int pricepernight { get; set; }
    public string currency { get; set; }
    public string refid { get; set; }
}

public class RoomDetails
{
    public List<Room> Rooms { get; set; }
    public string bookstartDate { get; set; }
    public string bookendDate { get; set; }
}

现有读取代码 #

string jsonFile = @"E:\hotel.json";
var json = File.ReadAllText(jsonFile);

var jsonObject = JObject.Parse(json);
JArray hotelbodyArrary = (JArray)jsonObject["body"];

if (hotelbodyArrary != null)
{
    Body body = new Body();
    Hotelbooking ho = new Hotelbooking();
    foreach (var item in hotelbodyArrary)
    {
        ho.paymentmode = Convert.ToString(item["paymentmode"]);
        ho.creditcardNumber = Convert.ToString(item["creditcardNumber"]);
    }

}

问题分析与解决方案 #

问题根源 #

现有代码取不到值的核心原因是节点路径错误：

• body数组里的每个元素是Body类型对象，而paymentmode、creditcardNumber这些字段属于Body对象下的hotelbooking数组中的Hotelbooking对象，并非直接在body元素下，所以item["paymentmode"]自然返回null。
• 手动逐层解析JSON不仅繁琐，还容易遗漏层级，出错概率高。

最优解决方案：用JSON序列化库自动映射 #

直接借助成熟的JSON序列化库（比如Newtonsoft.Json或System.Text.Json）完成自动映射，无需手动解析每个节点，高效且不易出错。

第一步：补充根实体类

JSON最外层包含header和body两个节点，需要新增一个根类来对应：

public class HotelBookingRoot
{
    public Header header { get; set; }
    public List<Body> body { get; set; }
}

第二步：用Newtonsoft.Json实现映射

如果项目中使用Newtonsoft.Json（Json.NET），代码如下：

using Newtonsoft.Json;
using System.IO;

string jsonFile = @"E:\hotel.json";
var jsonContent = File.ReadAllText(jsonFile);

// 一键反序列化到根对象
var hotelData = JsonConvert.DeserializeObject<HotelBookingRoot>(jsonContent);

// 示例：访问映射后的数据
if (hotelData?.body != null && hotelData.body.Count > 0)
{
    var firstBody = hotelData.body[0];
    Console.WriteLine($"客户ID：{firstBody.customerId}");
    
    if (firstBody.hotelbooking != null && firstBody.hotelbooking.Count > 0)
    {
        var firstBooking = firstBody.hotelbooking[0];
        Console.WriteLine($"支付方式：{firstBooking.paymentmode}");
        Console.WriteLine($"客户姓名：{firstBooking.Customer.Bookings.Profile.name}");
    }
}

第三步：用System.Text.Json实现映射（.NET Core/.NET 5+）

如果使用.NET自带的System.Text.Json，代码如下：

using System.Text.Json;
using System.IO;

string jsonFile = @"E:\hotel.json";
var jsonContent = File.ReadAllText(jsonFile);

// 一键反序列化到根对象
var hotelData = JsonSerializer.Deserialize<HotelBookingRoot>(jsonContent);

// 示例：访问映射后的数据
if (hotelData?.body != null && hotelData.body.Count > 0)
{
    var firstBody = hotelData.body[0];
    Console.WriteLine($"客户ID：{firstBody.customerId}");
    
    if (firstBody.hotelbooking != null && firstBody.hotelbooking.Count > 0)
    {
        var firstBooking = firstBody.hotelbooking[0];
        Console.WriteLine($"支付方式：{firstBooking.paymentmode}");
        Console.WriteLine($"客户姓名：{firstBooking.Customer.Bookings.Profile.name}");
    }
}

注意事项 #

• 确保实体类的属性名称和JSON节点名称完全一致（大小写敏感，除非配置序列化选项忽略大小写）。
• 如果使用System.Text.Json，对于DateTime类型的bookDateTime，默认可以正确解析ISO格式的时间字符串，无需额外配置。

内容的提问来源于stack exchange，提问作者Rahul Aggarwal