Question

在新的System.Text.Json中；命名空间中有类似IContractResolver的东西，我正在尝试从Newtonsoft迁移项目。

这是我要尝试的课程之一：

public class SelectiveSerializer : DefaultContractResolver
{
private readonly string[] fields;

public SelectiveSerializer(string fields)
{
  var fieldColl = fields.Split(',');
  this.fields = fieldColl
      .Select(f => f.ToLower().Trim())
      .ToArray();
}

protected override JsonProperty CreateProperty(MemberInfo member, MemberSerialization memberSerialization)
{
  var property = base.CreateProperty(member, memberSerialization);
  property.ShouldSerialize = o => fields.Contains(member.Name.ToLower());

  return property;
}
}

Answer 1

System.Text.Json中的等效类型-JsonClassInfo和 JsonPropertyInfo-是内部的。有一个开放的增强功能 System.Text.Json＃42001中的DefaultContractResolver的等效项要求公开等效。 – dbc 11月25日19:11

Github Issue

请尝试以下操作：
我将其编写为System.Text.Json的扩展，以提供缺少的功能：https://github.com/dahomey-technologies/Dahomey.Json。

您将找到对编程对象映射的支持。

定义您自己的IObjectMappingConvention实现：

public class SelectiveSerializer : IObjectMappingConvention
{
    private readonly IObjectMappingConvention defaultObjectMappingConvention = new DefaultObjectMappingConvention();
    private readonly string[] fields;

    public SelectiveSerializer(string fields)
    {
        var fieldColl = fields.Split(',');
        this.fields = fieldColl
            .Select(f => f.ToLower().Trim())
            .ToArray();
    }

    public void Apply<T>(JsonSerializerOptions options, ObjectMapping<T> objectMapping) where T : class
    {
        defaultObjectMappingConvention.Apply<T>(options, objectMapping);
        foreach (IMemberMapping memberMapping in objectMapping.MemberMappings)
        {
            if (memberMapping is MemberMapping<T> member)
            {
                member.SetShouldSerializeMethod(o => fields.Contains(member.MemberName.ToLower()));
            }
        }
    }
}

定义您的课程：

public class Employee
{
    public int Id { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public string Email { get; set; }
}

通过调用JsonSerializerOptions来设置json扩展，该扩展方法是在命名空间Dahomey.Json中定义的扩展方法SetupExtensions：

JsonSerializerOptions options = new JsonSerializerOptions();
options.SetupExtensions();

为该类注册新的对象映射约定：

options.GetObjectMappingConventionRegistry().RegisterConvention(
    typeof(Employee), new SelectiveSerializer("FirstName,Email,Id"));

然后使用常规的Sytem.Text.Json API序列化您的类：

Employee employee = new Employee
{
    Id = 12,
    FirstName = "John",
    LastName = "Doe",
    Email = "john.doe@acme.com"
};

string json = JsonSerializer.Serialize(employee, options);
// {"Id":12,"FirstName":"John","Email":"john.doe@acme.com"};

System.Text.Json API类似于IContractResolver

1 个答案: