我开始将已有的某些代码从 Newtonsoft.Json 迁移到 System.Text.Json Core 3.0应用。
I'm starting to migrate some code I have from Newtonsoft.Json to System.Text.Json in a Core 3.0 app.
我从
[JsonProperty( id)] 到 [JsonPropertyName( id)]
,但是我有一些属性装饰有 JsonConverter 属性为:
but I have some properties decorated with the JsonConverter attribute as:
[JsonConverter(typeof(DateTimeConverter))] [JsonPropertyName( birth_date)] DateTime BirthDate {get;组; }
但是我在 System.Text.Json 有人知道如何在 Core 3.0中实现吗?
But I cannot find the equivalent of this Newtonsoft converter in System.Text.Json Does someone know how can this be achieved in Core 3.0?
谢谢!
推荐答案System.Text.Json 现在在.NET 3.0 Preview-7及更高版本中支持自定义类型转换器。
System.Text.Json now supports custom type converters in .NET 3.0 preview-7 and above.
您可以添加类型匹配的转换器,并使用 JsonConverter 属性可为属性使用特定的转换器。
You can add converters that match on type, and use the JsonConverter attribute to use a specific converter for a property.
下面是在 long 和 string 之间进行转换的示例(因为javascript不支持64位整数)。
Here's an example to convert between long and string (because javascript doesn't support 64-bit integers).
public class LongToStringConverter : JsonConverter<long> { public override long Read(ref Utf8JsonReader reader, Type type, JsonSerializerOptions options) { if (reader.TokenType == JsonTokenType.String) { // try to parse number directly from bytes ReadOnlySpan<byte> span = reader.HasValueSequence ? reader.ValueSequence.ToArray() : reader.ValueSpan; if (Utf8Parser.TryParse(span, out long number, out int bytesConsumed) && span.Length == bytesConsumed) return number; // try to parse from a string if the above failed, this covers cases with other escaped/UTF characters if (Int64.TryParse(reader.GetString(), out number)) return number; } // fallback to default handling return reader.GetInt64(); } public override void Write(Utf8JsonWriter writer, long value, JsonSerializerOptions options) { writer.WriteStringValue(value.ToString()); } }通过将转换器添加到<$ c中进行注册 JsonSerializerOptions
services.AddControllers().AddJsonOptions(options => { options.JsonSerializerOptions.Converters.Add(new LongToStringConverter()); });注意:当前版本尚不支持可空类型。
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