创建可屏蔽敏感信息的自定义 json 转换器

Question

我正在编写一个自定义 json 转换器，它将序列化一个对象并屏蔽包含一些敏感信息的某些字段。我已经创建了转换器，但是当我使用转换器序列化对象时，我得到一个空字符串。有人能告诉我我做错了什么吗？

public class Student

{

    public string Name { get; set; }

    public string Phone { get; set; }

}

class StudentJsonConverter : JsonConverter

{

    /// <inheritdoc />

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)

    {

        if (value is Student student)

        {

            student.Phone = MaskString(student.Phone);

        }

        writer.WriteStartObject();

        serializer.Serialize(writer, value);

        writer.WriteEndObject();

    }

    /// <inheritdoc />

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)

    {

        throw new NotImplementedException();

    }

    /// <inheritdoc />

    public override bool CanConvert(Type objectType) => typeof(Student) == objectType;

    private static string MaskString(string sensitiveInformation) => string.IsNullOrWhiteSpace(sensitiveInformation) ? null : new string('*', sensitiveInformation.Length);

}

我在这里使用它：

    JsonSerializerSettings settings = new JsonSerializerSettings();

    settings.Converters.Add(new StudentJsonConverter());

    settings.ReferenceLoopHandling = ReferenceLoopHandling.Ignore;

    var student = new Student { Name = "name", Phone = "1234" };

    var serializedString = JsonConvert.SerializeObject(student, settings);

    Console.WriteLine(serializedString);

但我总是得到一个空字符串。