Question

我有以下格式的JSON（来自couchDB视图）

{"rows":[
  {"key":["2015-04-01","524","http://www.sampleurl.com/"],"value":1},
  {"key":["2015-04-01","524","http://www.sampleurl2.com/"],"value":2},
  {"key":["2015-04-01","524","http://www.sampleurl3.com"],"value":1}
]}

我需要创建一个＆＃34;服务＆＃34;从couchDB获取此数据并以有效的方式将其插入SQL Server（用于生成报告..）。我的第一个赌注是将这个json批量插入SQL Server，如下所示：Bulk Insert from Generic List into SQL Server with minimum lines of code

问题是，如何将此JSON映射到c＃类？

Ultil现在这就是我所做的：

public class Row
{
    public List<string> key { get; set; }
    public int value { get; set; }
}

public class RootObject
{
    public List<Row> rows { get; set; }
}

var example = Newtonsoft.Json.JsonConvert.DeserializeObject<RootObject>(jsontext);

这给了我一个＆＃34;行＆＃34;的列表。每行都有一个Key，每个键都是一个包含Date，Url和数字的数组。

我可以遍历＆＃34;行＆＃34;并且我自己创造了这些物体但这对我来说听起来非常有效。此外，JSON会很大，大概是5MB或更少。

我想要的结构是这样的：

public class Click
{
    public DateTime Date { get; set; }
    public string Code { get; set; }
    public string Url { get; set; }
    public int Count { get; set; }
}

如何提取＆＃34;键＆＃34;数组并将其映射到分隔的属性中。这样，我就不需要for循环了。

有什么想法吗？

Answer 1

你在这里。

public class Row
{
    // Serialize/Deserialize the `key` into it's values.
    public List<string> key { get { return new List<string>() { Date.ToString("yyyy-MM-dd"), Code, Url }; } set { Date = DateTime.Parse(value[0]); Code = value[1]; Url = value[2]; } }
    // Serialize/Deserialize the `value` into `Count`.
    public int value { get { return Count; } set { Count = value; } }

    [ScriptIgnore]
    public DateTime Date { get; set; }
    [ScriptIgnore]
    public string Code { get; set; }
    [ScriptIgnore]
    public string Url { get; set; }
    [ScriptIgnore]
    public int Count { get; set; }

    public override string ToString()
    {
        return Date.ToString("yyyy-MM-dd") + ", " + Code + ", " + Url + ", " + Count;
    }
}

public class RootObject
{
    public List<Row> rows { get; set; }
}

public static void _Main(string[] args)
{
    string json = "{\"rows\":[" +
        "{\"key\":[\"2015-04-01\",\"524\",\"http://www.sampleurl.com/\"],\"value\":1}," +
        "{\"key\":[\"2015-04-01\",\"524\",\"http://www.sampleurl2.com/\"],\"value\":2}," +
        "{\"key\":[\"2015-04-01\",\"524\",\"http://www.sampleurl3.com\"],\"value\":1}" + 
        "]}";

    var jss = new JavaScriptSerializer();
    var example = jss.Deserialize<RootObject>(json);

    foreach (Row r in example.rows)
    {
        Console.WriteLine(r.ToString());
    }
}

它应该是不言自明的。如果你想让我详细询问。但是，要求元素始终保持一致的顺序。

以上输出：

2015-04-01, 524, http://www.sampleurl.com/, 1
2015-04-01, 524, http://www.sampleurl2.com/, 2
2015-04-01, 524, http://www.sampleurl3.com, 1

这种方法的明显好处是它具有低开销。它也很容易维护。这也意味着您显然可以在其上具有XmlIgnoreAttribute的属性上提供ScriptIgnoreAttribute，并且还可以生成和读取有效的序列化XML。

注意：我使用了System.Web.Script.Serialization.JavaScriptSerializer。如果JSON.NET不使用ScriptIgnoreAttribute，则您必须应用它使用的任何属性。（我从未使用JSON.NET。）

另一个注意：我是针对C#6.0和.NET 4.6写的。您的结果可能会有所不同。

Answer 2

您可以为此创建自定义JsonConverter：

[JsonConverter(typeof(ClickConverter))]
public class Click
{
    public DateTime Date { get; set; }
    public string Code { get; set; }
    public string Url { get; set; }
    public int Count { get; set; }
}

public class ClickConverter : JsonConverter
{
    public override bool CanConvert(Type objectType)
    {
        return typeof(Click).IsAssignableFrom(objectType);
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
    {
        var token = JToken.Load(reader);
        if (token == null || token.Type == JTokenType.Null)
            return null;
        var click = (existingValue as Click ?? new Click());
        var key = token["key"] as JArray;
        if (key != null && key.Count > 0)
            click.Date = (DateTime)key[0];
        if (key != null && key.Count > 1)
            click.Code = (string)key[1];
        if (key != null && key.Count > 2)
            click.Url = (string)key[2];
        var value = token["value"];
        if (value != null)
            click.Count = (int)value;
        return click;
    }

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
    {
        // Fill in with the opposite of the code above, if needed
        var click = value as Click;
        if (click == null)
            writer.WriteNull();
        else
            serializer.Serialize(writer,
                new
                {
                    // Update the date string format as appropriate
                    // https://msdn.microsoft.com/en-us/library/8kb3ddd4%28v=vs.110%29.aspx
                    key = new string[] { click.Date.ToString("yyyy-MM-dd", CultureInfo.InvariantCulture), click.Code.ToString(CultureInfo.InvariantCulture), click.Url },
                    value = click.Count
                });
    }
}

public class RootObject
{
    public List<Click> rows { get; set; }
}

将转换器直接应用于类后，您可以像往常一样（反）序列化：

        var jsontext = @"{""rows"":[
  {""key"":[""2015-04-01"",""524"",""http://www.sampleurl.com/""],""value"":1},
  {""key"":[""2015-04-01"",""524"",""http://www.sampleurl2.com/""],""value"":2},
  {""key"":[""2015-04-01"",""524"",""http://www.sampleurl3.com""],""value"":1}
]}";
        var rows = JsonConvert.DeserializeObject<RootObject>(jsontext);
        Debug.WriteLine(JsonConvert.SerializeObject(rows, Formatting.Indented));

将JSON反序列化为c＃类

2 个答案: