使用 Unity 的 JsonUtility.FromJson 反序列化嵌套的 JSON

Question

我已经写了两个测试，试图分别将成功和失败的平面和嵌套对象进行序列化，如下所示：

using NUnit.Framework;
using UnityEngine;
namespace Tests
{
  public class FromJson
  {
    [Test]
    public void Flat()
    {
      string json = "{"data":"foo"}";
      Flat deserialized = JsonUtility.FromJson<Flat>(json);
      Assert.AreEqual(deserialized.data, "foo");
      var reserialized = JsonUtility.ToJson(deserialized);
      Assert.AreEqual(json, reserialized);
    }
    [Test]
    public void Nested() 
    {
      string json = "{"data":{"data":"foo"}}";
      Nested deserialized = JsonUtility.FromJson<Nested>(json);
      Assert.AreEqual(deserialized.data.data, "foo");
      var reserialized = JsonUtility.ToJson(deserialized);
      Assert.AreEqual(json, reserialized);
    }
  }
}
public class Flat
{
  public string data;
}
public class Nested
{
  public Data data;
}
public class Data
{
  public string data;
}

失败的输出看起来如下：

Nested (0.009s)
---
System.NullReferenceException : Object reference not set to an instance of an object
---
at Tests.FromJson.Nested () [0x0000e] in /Users/bgates/Unity/Virtual Store/Assets/Tests/Serialization.cs:23 
  at (wrapper managed-to-native) System.Reflection.MonoMethod.InternalInvoke(System.Reflection.MonoMethod,object,object[],System.Exception&)
  at System.Reflection.MonoMethod.Invoke (System.Object obj, System.Reflection.BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x00032] in <ac823e2bb42b41bda67924a45a0173c3>:0

任何帮助将不胜感激。谢谢！

Answer 1

事实证明我缺少 [System.Serializable]。

以下测试通过：

using NUnit.Framework;
using UnityEngine;
namespace Tests
{
  public class FromJson
  {
    [Test]
    public void Flat()
    {
      string json = "{"foo":"bar"}";
      Flat deserialized = JsonUtility.FromJson<Flat>(json);
      Assert.AreEqual(deserialized.foo, "bar");
      var reserialized = JsonUtility.ToJson(deserialized);
      Assert.AreEqual(json, reserialized);
    }
    [Test]
    public void Nested()
    {
      string json = "{"foo":{"foo":"bar"}}";
      Nested deserialized = JsonUtility.FromJson<Nested>(json);
      Assert.AreEqual(deserialized.foo.foo, "bar");
      var reserialized = JsonUtility.ToJson(deserialized);
      Assert.AreEqual(json, reserialized);
    }
  }
}
[System.Serializable]
class Foo
{
  public string bar;
}
[System.Serializable]
public class Flat
{
  public string foo;
}
[System.Serializable]
public class Nested
{
  public Foo2 foo;
}
[System.Serializable]
public class Foo2
{
  public string foo;
}