Unity3D - 无法将 JSON 反序列化为 object

Question

我有这个 JSON 响应：

{
  "trainServices": [
    {
      "origin": [
        {
          "locationName": "Somewhere",
          "crs": "smw",
          "via": null,
          "futureChangeTo": null,
          "assocIsCancelled": false
        }
      ],
      "destination": [
        {
          "locationName": "Somewhere",
          "crs": "smw",
          "via": null,
          "futureChangeTo": null,
          "assocIsCancelled": false
        }
      ],
      "currentOrigins": null,
      "currentDestinations": null,
      "rsid": "NT208200",
      "sta": null,
      "eta": null,
      "std": "21:07",
      "etd": "21:10",
      "platform": "1",
      "operator": "Northern",
      "operatorCode": "NT",
      "isCircularRoute": false,
      "isCancelled": false,
      "filterLocationCancelled": false,
      "serviceType": 0,
      "length": 2,
      "detachFront": false,
      "isReverseFormation": false,
      "cancelReason": null,
      "delayReason": null,
      "adhocAlerts": null
    },
    {
      "origin": [
        {
          "locationName": "Somewhere",
          "crs": "smw",
          "via": null,
          "futureChangeTo": null,
          "assocIsCancelled": false
        }
      ],
      "destination": [
        {
          "locationName": "Somewhere",
          "crs": "smw",
          "via": null,
          "futureChangeTo": null,
          "assocIsCancelled": false
        }
      ],
      "currentOrigins": null,
      "currentDestinations": null,
      "rsid": "NT224200",
      "sta": null,
      "eta": null,
      "std": "21:42",
      "etd": "On time",
      "platform": "2",
      "operator": "Northern",
      "operatorCode": "NT",
      "isCircularRoute": false,
      "isCancelled": false,
      "filterLocationCancelled": false,
      "serviceType": 0,
      "length": 2,
      "detachFront": false,
      "isReverseFormation": false,
      "cancelReason": null,
      "delayReason": null,
      "adhocAlerts": null
    },
    {
      "origin": [
        {
          "locationName": "Somewhere",
          "crs": "smw",
          "via": null,
          "futureChangeTo": null,
          "assocIsCancelled": false
        }
      ],
      "destination": [
        {
          "locationName": "Somewhere",
          "crs": "smw",
          "via": null,
          "futureChangeTo": null,
          "assocIsCancelled": false
        }
      ],
      "currentOrigins": null,
      "currentDestinations": null,
      "rsid": "NT208300",
      "sta": null,
      "eta": null,
      "std": "22:07",
      "etd": "On time",
      "platform": "1",
      "operator": "Northern",
      "operatorCode": "NT",
      "isCircularRoute": false,
      "isCancelled": false,
      "filterLocationCancelled": false,
      "serviceType": 0,
      "length": 3,
      "detachFront": false,
      "isReverseFormation": false,
      "cancelReason": null,
      "delayReason": null,
      "adhocAlerts": null
    },
    {
      "origin": [
        {
          "locationName": "Somewhere",
          "crs": "smw",
          "via": null,
          "futureChangeTo": null,
          "assocIsCancelled": false
        }
      ],
      "destination": [
        {
          "locationName": "Somewhere",
          "crs": "smw",
          "via": null,
          "futureChangeTo": null,
          "assocIsCancelled": false
        }
      ],
      "currentOrigins": null,
      "currentDestinations": null,
      "rsid": "NT224700",
      "sta": null,
      "eta": null,
      "std": "22:52",
      "etd": "On time",
      "platform": "2",
      "operator": "Northern",
      "operatorCode": "NT",
      "isCircularRoute": false,
      "isCancelled": false,
      "filterLocationCancelled": false,
      "serviceType": 0,
      "length": 3,
      "detachFront": false,
      "isReverseFormation": false,
      "cancelReason": null,
      "delayReason": null,
      "adhocAlerts": null
    }
  ],
  "busServices": null,
  "ferryServices": null,
  "generatedAt": "2019-10-01T20:03:23.2126313+00:00",
  "locationName": "Somewhere",
  "crs": "smw",
  "filterLocationName": null,
  "filtercrs": null,
  "filterType": 0,
  "nrccMessages": null,
  "platformAvailable": true,
  "areServicesAvailable": true
}

我正在尝试使用以下类转换为 object：

[System.Serializable]
public class TrainJsonResponse : MonoBehaviour
{
    public TrainServices[] trainServices;   
}

[System.Serializable]
public class TrainServices
{
    public Origin[] origin;
    public string std;
    public string etd;
}

[System.Serializable]
public class Origin
{
    public string locationName;
}

使用JsonUtility.FromJson方法：

TrainJsonResponse trainData = JsonUtility.FromJson<TrainJsonResponse>(jsonResponse);

但是当我尝试这样做时，我得到一个错误：

ArgumentException: Cannot deserialize JSON to new instances of type 'TrainJsonResponse.'

据我了解，我只使用 JSON 响应中的两到三个字段这一事实无关紧要，Unity 应该跳过/忽略这些字段和 map 它可以做什么？

我的反序列化做错了什么？ :-)

Answer 1

问题是您的TrainJsonResponse从MonoBehaviour扩展，而JsonUtility无法反序列化MonoBehaviour 。 你应该把它改成这样：

[System.Serializable]
public class TrainJsonResponse
{
    public TrainServices[] trainServices;   
}

[System.Serializable]
public class TrainServices
{
    public Origin[] origin;
    public string std;
    public string etd;
}

[System.Serializable]
public class Origin
{
    public string locationName;
}

Answer 2

对于从 MonoBehaviour 继承的对象，当您反序列化它时，您必须使用 JsonUtility.FromJsonOverwrite 与 JsonUtility.FromJson，因为“JsonUtility.FromJsonOverwrite”不会尝试由构造函数创建新的 MonoBehaviour 实例，这是不允许的。

警告：JSON 序列化器 API 支持 MonoBehaviour 和 ScriptableObject 子类以及普通结构和类。 但是，在将 JSON 反序列化为 MonoBehaviour 或 ScriptableObject 的子类时，必须使用 FromJsonOverwrite 方法。 如果您尝试使用 FromJson，Unity 会抛出异常，因为此行为不受支持。 JSON 序列化

Answer 3

我有一个类似的问题，但这是因为我反序列化到的 class 被标记为abstract ，删除了abstract关键字并且它工作正常。