使用JsonConverter在C#中自定义JSON反序列化

问题描述：

.Net Core中有两个类

I have two classes in .Net Core

类所有权

namespace CustomStoreDatabase.Models
{
    public class Ownership
    {
        public string OwnershipId { get; set; }
        public List<string> TextOutput { get; set; }
        public DateTime DateTime { get; set; }
        public TimeSpan MeanInterval { get; set; }// Like long ticks, TimeSpan.FromTicks(Int64), TimeSpan.Ticks
    }
}

我需要使用方法 TimeSpan.FromTicks(Int64)和 TimeSpan.Ticks 像长刻度一样显示 MeanInterval .

I need to show MeanInterval like long ticks, using the methods TimeSpan.FromTicks(Int64) and TimeSpan.Ticks.

我的自定义JsonConverter

My custom JsonConverter

using CustomStoreDatabase.Models;
using System;
using System.Text.Json;
using System.Text.Json.Serialization;

namespace CustomStoreDatabase.Util
{
    public class OwnershipJSonConverter : JsonConverter<Ownership>
    {
        public override bool CanConvert(Type typeToConvert)
        {
            return true;
        }

        public override Ownership Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
        {
            if (reader.TokenType != JsonTokenType.StartObject)
            {
                throw new JsonException();
            }
            //*******************
            // HOW TO IMPLEMENT?
            //*******************
            //throw new NotImplementedException();
        }

        public override void Write(Utf8JsonWriter writer, Ownership value, JsonSerializerOptions options)
        {
            writer.WriteStartObject();
            if (value != null)
            {
                writer.WriteString("OwnershipId", value.OwnershipId);
                writer.WriteString("TextOutput", JsonSerializer.Serialize(value.TextOutput));
                writer.WriteString("DateTime", JsonSerializer.Serialize(value.DateTime));
                if (value.MeanInterval != null)
                {
                    writer.WriteNumber("MeanInterval", (long)value.MeanInterval.Ticks);
                }
                else
                {
                    writer.WriteNull("MeanInterval");
                }
            }
            writer.WriteEndObject();
        }
    }
}

我不知道如何实现 Read 方法.如何实现覆盖Read方法的自定义反序列化?

I don't know how to implement the Read method. How can I implement the custom Deserialization overriding the Read method?

如果可能的话，我向我提议了 CanConvert 方法的另一种实现，非常感谢.

If is possible you guys proposal to me another implementation for CanConvert method, I thank you very much.

答

似乎您只想对 TimeSpan 进行自定义序列化，因为它属于 Ownership ，因此为什么不只为 TimeSpan 创建转换器，并避免手动序列化所有其他类属性呢?

It seems like you only want to perform custom serialization of TimeSpan as it belongs to Ownership, so why not make a converter for TimeSpan only and save yourself from manually serializing all of the other class properties?:

public class TimeSpanConverter : JsonConverter<TimeSpan>
{
    public override TimeSpan Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
    {
        return TimeSpan.FromTicks(reader.GetInt64());
    }

    public override void Write(Utf8JsonWriter writer, TimeSpan value, JsonSerializerOptions options)
    {
        writer.WriteNumberValue(value.Ticks);
    }
}

然后用 JsonConverterAttribute 装饰您的 MeanInterval 属性:

public class Ownership
{
    public string OwnershipId { get; set; }
    public List<string> TextOutput { get; set; }
    public DateTime DateTime { get; set; }
    [JsonConverter(typeof(TimeSpanConverter))]
    public TimeSpan MeanInterval { get; set; }// Like long ticks, TimeSpan.FromTicks(Int64), TimeSpan.Ticks
}

在线试用

使用JsonConverter在C#中自定义JSON反序列化

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