Newtonsoft Json.net – 如何序列化流的内容？

我需要转换为内存流的JSON 任意内容 。 这是我想要做的一个简单示例：

class Program { class TestClass { public int Test1;} static void Main(string[] args) { var ms = new MemoryStream(); var writer = new StreamWriter(ms); writer.Write(new TestClass()); writer.Flush(); ms.Position = 0; var json = JsonConvert.SerializeObject(/*???*/, Formatting.Indented); Console.Write(json); Console.Read(); } } 

不知道要传递给SerializeObject方法的内容。 如果我传递MemoryStream（变量ms）我得到一个错误：

Newtonsoft.Json.dll中出现未处理的“Newtonsoft.Json.JsonSerializationException”类型exception

附加信息：从’System.IO.MemoryStream’上的’ReadTimeout’获取值时出错。

是否可以序列化流的任意内容？

谢谢

Answer 1

使用转换器可以实现对MemoryStream内容的序列化和反序列化：

 public class MemoryStreamJsonConverter : JsonConverter { public override bool CanConvert(Type objectType) { return typeof(MemoryStream).IsAssignableFrom(objectType); } public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer) { var bytes = serializer.Deserialize(reader); return bytes != null ? new MemoryStream(bytes) : new MemoryStream(); } public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer) { var bytes = ((MemoryStream)value).ToArray(); serializer.Serialize(writer, bytes); } } 

然后你的代码看起来像那样（我将“new TestClass（）”更改为“Test string”以便于比较json序列化和反序列化）：

 private void CheckJsonSerialization() { var ms = new MemoryStream(); var writer = new StreamWriter(ms); writer.WriteLine("Test string"); writer.Flush(); ms.Position = 0; var json = JsonConvert.SerializeObject(ms, Formatting.Indented, new MemoryStreamJsonConverter()); var ms2 = JsonConvert.DeserializeObject(json, new MemoryStreamJsonConverter()); var reader = new StreamReader(ms2); var deserializedString = reader.ReadLine(); Console.Write(json); Console.Write(deserializedString); Console.Read(); } 

当Stream是序列化对象的属性时，也可以使用这种转换器：

  public class ClassToCheckSerialization { public string StringProperty { get; set; } [JsonConverter(typeof(MemoryStreamJsonConverter))] public Stream StreamProperty { get; set; } } private void CheckJsonSerializationOfClass() { var data = new ClassToCheckSerialization(); var ms = new MemoryStream(); const string entryString = "Test string inside stream"; var sw = new StreamWriter(ms); sw.WriteLine(entryString); sw.Flush(); ms.Position = 0; data.StreamProperty = ms; var json = JsonConvert.SerializeObject(data); var result = JsonConvert.DeserializeObject(json); var sr = new StreamReader(result.StreamProperty); var stringRead = sr.ReadLine(); //Assert.AreEqual(entryString, stringRead); }