与json.net flatten nested json在C＃中

Question

我通过WebAPI收到JSON格式的材料清单，该WebAPI具有相应的层次结构。 层次结构或嵌套可以是任何深度。

材料清单如下所示：

{
   "Quantity":0,
   "QuantityUnit":"pcs",
   "PartNumber":"12345",
   "Parent":"",
   "Children":[
      {
         "Quantity":1,
         "QuantityUnit":"pcs",
         "PartNumber":"88774",
         "Parent":"12345",
         "Children":[
            {
               "Quantity":1,
               "QuantityUnit":"pcs",
               "PartNumber":"42447",
               "Parent":"88774"
            },
            {
               "Quantity":0.420,
               "QuantityUnit":"kg",
               "PartNumber":"12387",
               "Parent":"88774"
            }
         ]
      }
   ]
}

如何使用C＃中的JSON.NET将此嵌套结构解析为一个简单的结构？

我想将其转换为：

[
   {
      "Quantity":0,
      "QuantityUnit":"pcs",
      "PartNumber":"12345",
      "Parent":""
   },
   {
      "Quantity":1,
      "QuantityUnit":"pcs",
      "PartNumber":"88774",
      "Parent":"12345"
   },
   {
      "Quantity":1,
      "QuantityUnit":"pcs",
      "PartNumber":"42447",
      "Parent":"88774"
   },
   {
      "Quantity":0.420,
      "QuantityUnit":"kg",
      "PartNumber":"12387",
      "Parent":"88774"
   }
]

对于避难所化，我使用以下类：

public class Bom
{
    public class TopLevel
    {
        public double Quantity { get; set; }
        public string QuantityUnit { get; set; }
        public string PartNumber { get; set; }
        public string Parent { get; set; }
        public List<Item> Children { get; set; }
    }

    public class Item
    {
        public double Quantity { get; set; }
        public string QuantityUnit { get; set; }
        public string PartNumber { get; set; }
        public string Parent { get; set; }
    }

    public double Quantity { get; set; }
    public string QuantityUnit { get; set; }
    public string PartNumber { get; set; }
    public string Parent { get; set; }
    public IList<TopLevel> Children { get; set; }
}

此外，我还使用此代码将JSON验证为对象：

Bom bom = JsonConvert.DeserializeObject<Bom>(File.ReadAllText(jsonPath));

Answer 1

首先，让我们定义映射器

JObject Map(JObject source)
{
    var result = (JObject)source.DeepClone();
    result.Remove("Children");
    return result;
}

• ，它只是夹住对象并删除 children 属性

接下来，让我们定义一个递归功能以累积 jobign s

void Flatten(JArray children, JArray accumulator)
{
    if (children == null) return;
    foreach (JObject child in children)
    {
        accumulator.Add(Map(child));
        Flatten((JArray)child["Children"], accumulator);
    }
}

，最后让我们使用它们

var semiParsed = JObject.Parse(json);

var accumulator = new JArray();
accumulator.Add(Map(semiParsed));
Flatten((JArray)semiParsed["Children"], accumulator);

toString 在累加器上调用将返回此

[
  {
    "Quantity": 0,
    "QuantityUnit": "pcs",
    "PartNumber": "12345",
    "Parent": ""
  },
  {
    "Quantity": 1,
    "QuantityUnit": "pcs",
    "PartNumber": "88774",
    "Parent": "12345"
  },
  {
    "Quantity": 1,
    "QuantityUnit": "pcs",
    "PartNumber": "42447",
    "Parent": "88774"
  },
  {
    "Quantity": 0.42,
    "QuantityUnit": "kg",
    "PartNumber": "12387",
    "Parent": "88774"
  }
]

---

更新＃1

如果您的源JSON包含深层层次结构（假设超过5个级别），则 DeepClone 并不是真正有效的，因为您要复制整个子树。

要解决此问题，您只需要重写 MAP 函数

JObject Map(JObject source)
=> JObject.FromObject(new
{
    Quantity = (double)source["Quantity"],
    QuantityUnit = (string)source["QuantityUnit"],
    PartNumber = (string)source["PartNumber"],
    Parent = (string)source["Parent"]
});

Answer 2

应对原始列表进行挑选，用 enumerable.selectmany ，并序列化结果序列。