Question

我正在使用JavaScriptSerializer来序列化一些实体对象。

问题是，许多公共属性包含null或默认值。有没有办法让JavaScriptSerializer排除具有null或默认值的属性？

我希望生成的JSON不那么详细。

Answer 1

仅供参考，如果您想使用更简单的解决方案，以下是我使用JavaScriptSvertizer的JavaScriptConverter实现实现此目的：

    private class NullPropertiesConverter : JavaScriptConverter
    {
        public override object Deserialize(IDictionary<string, object> dictionary, Type type, JavaScriptSerializer serializer)
        {
            throw new NotImplementedException();
        }

        public override IDictionary<string, object> Serialize(object obj, JavaScriptSerializer serializer)
        {
            var jsonExample = new Dictionary<string, object>();
            foreach (var prop in obj.GetType().GetProperties())
            {
               //check if decorated with ScriptIgnore attribute
               bool ignoreProp = prop.IsDefined(typeof(ScriptIgnoreAttribute), true);

                var value = prop.GetValue(obj, BindingFlags.Public, null, null, null);
                if (value != null && !ignoreProp)
                    jsonExample.Add(prop.Name, value);
            }

            return jsonExample;
        }

        public override IEnumerable<Type> SupportedTypes
        {
            get { return GetType().Assembly.GetTypes(); }
        }
    }

然后使用它：

    var serializer = new JavaScriptSerializer();
    serializer.RegisterConverters(new JavaScriptConverter[] { new NullPropertiesConverter() });
    return serializer.Serialize(someObjectToSerialize);

Answer 2

对我有用的解决方案：

序列化的类和属性将按如下方式进行修饰：

[DataContract]
public class MyDataClass
{
  [DataMember(Name = "LabelInJson", IsRequired = false)]
  public string MyProperty { get; set; }
}

IsRequired是关键项目。

实际的序列化可以使用DataContractJsonSerializer完成：

public static string Serialize<T>(T obj)
{
  string returnVal = "";
  try
  {
    DataContractJsonSerializer serializer = new DataContractJsonSerializer(obj.GetType());
    using (MemoryStream ms = new MemoryStream())
    {
      serializer.WriteObject(ms, obj);
      returnVal = Encoding.Default.GetString(ms.ToArray());
    }
  }
  catch (Exception /*exception*/)
  {
    returnVal = "";
    //log error
  }
  return returnVal;
}

Answer 3

Json.NET具有自动排除空值或默认值的选项。

Answer 4

您可以实施JavaScriptConverter并使用JavaScriptSerializer的{{3}}方法进行注册。

Answer 5

此代码为null null，数值类型的默认值为（0）

    private class NullPropertiesConverter : JavaScriptConverter
    {
        public override object Deserialize(IDictionary<string, object> dictionary, Type type, JavaScriptSerializer serializer)
        {
            throw new NotImplementedException();
        }

        public override IDictionary<string, object> Serialize(object obj, JavaScriptSerializer serializer)
        {
            var jsonExample = new Dictionary<string, object>();
            foreach (var prop in obj.GetType().GetProperties())
            {
                //this object is nullable 
                var nullableobj = prop.PropertyType.IsGenericType && prop.PropertyType.GetGenericTypeDefinition() == typeof(Nullable<>);
                //check if decorated with ScriptIgnore attribute
                bool ignoreProp = prop.IsDefined(typeof(ScriptIgnoreAttribute), true);

                var value = prop.GetValue(obj, System.Reflection.BindingFlags.Public, null, null, null);
                int i;
                //Object is not nullable and value=0 , it is a default value for numeric types 
                if (!(nullableobj == false && value != null && (int.TryParse(value.ToString(), out i) ? i : 1) == 0) && value != null && !ignoreProp)
                    jsonExample.Add(prop.Name, value);
            }

            return jsonExample;
        }

        public override IEnumerable<Type> SupportedTypes
        {
            get { return GetType().Assembly.GetTypes(); }
        }
    }

Answer 6

不改变脚趾DataContractSerializer

您可以使用ScriptIgnoreAttribute

[1] http://msdn.microsoft.com/en-us/library/system.web.script.serialization.scriptignoreattribute.aspx

Answer 7

为了让那些在谷歌上找到这个的人受益，请注意在使用Newtonsoft.Json序列化期间可以原生跳过空值

var json = JsonConvert.SerializeObject(
            objectToSerialize,
            new JsonSerializerSettings {NullValueHandling = NullValueHandling.Ignore});

JavaScriptSerializer可以排除具有null / default值的属性吗？

7 个答案: