C# 将 Json 转换为 CSV

Question

我有一个 json 文件，格式如下：

{
"HDRDTL":["SRNO","STK_IDN","CERTIMG"],
"PKTDTL":[
{"SRNO":"2814","STK_IDN":"1001101259","CERTIMG":"6262941723"},
{"SRNO":"2815","STK_IDN":"1001101269","CERTIMG":"6262941726"},
{"SRNO":"2816","STK_IDN":"1001101279","CERTIMG":"6262941729"}
],
"IMGTTL":
["CERTIMG","ARRIMG"],
"IMGDTL":{"CERTIMG":"CRd6z2uq3gvx7kk","ARRIMG":"ASd6z2uq3gvx7kk"}
}

"PKTDTL" 数组是我需要转换为 csv 的部分。我如何在 C# 中实现这一点？

注意，举个例子，我在 "PKTDTL" 中只有 3 个项目，真正的 json 文件有几千行 ({"SRNO" ...}) 和很大。

我写了下面的代码，但没有用。请参阅代码中注释的错误消息。

问题

有人知道为什么失败吗？

你有better/alternative方法吗

public static void ConvertJsonToCSV(string InFile)
{

string OutFile=InFile.Replace("json","csv");

StreamReader sInFile = new StreamReader(InFile);
StreamWriter sOutFile = new StreamWriter(OutFile);

using (sInFile)
{
    string sJson = sInFile.ReadToEnd();

    //*************************************************************
    // the below line failed, error message: unexpected json token
    // when reading datatable, expected startArray, got StartObject.
    //**************************************************************

    DataTable dt = JsonConvert.DeserializeObject<DataTable>(sJson);
    //DataTable dt = JsonConvert.DeserializeAnonymousType(sJson, new { Makes = default(DataTable) }).Makes;

    var sb = new StringBuilder();

    string[] columnNames = (from dc in dt.Columns.Cast<DataColumn>()
                            select dc.ColumnName).ToArray();

    sb.AppendLine(string.Join(",", columnNames));

    foreach (DataRow dr in dt.Rows)
    {
        foreach (object field in dr.ItemArray)
        {
            sb.Append(field.ToString().Replace(",", "") + ",");
        }
        sb.Replace(",", "\n", sb.Length - 1, 1);
    }

    sOutFile.Write(sb.ToString());

    sOutFile.Close();
    sInFile.Close();
}

}

Answer 1

我发现自己处于类似情况。这就是我所做的。首先，我创建了一个 JObject（使用 Newtonsoft.Json.Linq）让我们考虑一下您的 json 在一个名为 "strJSON".

的字符串变量中

 JObject jsonObj= JObject.parse(strJSON);
 JObject  PKTDL=jsonObj["PKTDTL"] as JObject;
 IList<string> keys = PKTDL.Properties().Select(p => p.Name).ToList(); // this gives column names
 StringBuilder sb=new StringBuilder();
 string headers="";
 foreach(string key in keys)
 {
   headers+=","+key;
 }  
 sb.AppendLine(headers.TrimStart(','));
 foreach(JObject j in jsonObj["PKTDTL"]) //if jobject doesnt work try "JToken j"
 {
    string values="";
    foreach(string key in keys)
    {
       values+=","+jsonObj["PKTDTL"][key];
    }
    sb.AppendLine(values.TrimStart(','));
 }

   File.WriteAllText(filePath, sb.ToString());

然后将 sb 另存为 csv

Answer 2

使用 Cinchoo ETL - 开源库，只需几行代码即可轻松完成转换

string json = @"{
    ""HDRDTL"":[""SRNO"",""STK_IDN"",""CERTIMG""],
    ""PKTDTL"":[
    {""SRNO"":""2814"",""STK_IDN"":""1001101259"",""CERTIMG"":""6262941723""},
    {""SRNO"":""2815"",""STK_IDN"":""1001101269"",""CERTIMG"":""6262941726""},
    {""SRNO"":""2816"",""STK_IDN"":""1001101279"",""CERTIMG"":""6262941729""}
    ],
    ""IMGTTL"":
    [""CERTIMG"",""ARRIMG""],
    ""IMGDTL"":{""CERTIMG"":""CRd6z2uq3gvx7kk"",""ARRIMG"":""ASd6z2uq3gvx7kk""}
    }";

StringBuilder sb = new StringBuilder();
using (var p = ChoJSONReader.LoadText(json).WithJSONPath("$..PKTDTL")
    )
{
    using (var w = new ChoCSVWriter(sb)
        .WithFirstLineHeader()
        )
        w.Write(p);
}

Console.WriteLine(sb.ToString());

输出：

SRNO,STK_IDN,CERTIMG
2814,1001101259,6262941723
2815,1001101269,6262941726
2816,1001101279,6262941729

查看 CodeProject 文章以获得更多帮助。

免责声明：我是这个库的作者。

Answer 3

与 (see the JsonToCsv(string, string) method there). If you are already using NewtonSoft Json.NET and CsvHelper you can do similar conversion with the help of ExpandoObject类似的问题。

    var jsonText = @"{
        ""HDRDTL"":[""SRNO"",""STK_IDN"",""CERTIMG""],
        ""PKTDTL"":[
        {""SRNO"":""2814"",""STK_IDN"":""1001101259"",""CERTIMG"":""6262941723""},
        {""SRNO"":""2815"",""STK_IDN"":""1001101269"",""CERTIMG"":""6262941726""},
        {""SRNO"":""2816"",""STK_IDN"":""1001101279"",""CERTIMG"":""6262941729""}
        ],
        ""IMGTTL"":
        [""CERTIMG"",""ARRIMG""],
        ""IMGDTL"":{""CERTIMG"":""CRd6z2uq3gvx7kk"",""ARRIMG"":""ASd6z2uq3gvx7kk""}
        }";

    var jtoken = JObject.Parse(jsonText).SelectToken("$..PKTDTL");
    var expandos = jtoken.ToObject<ExpandoObject[]>();
    string csvText;

    using (var writer = new StringWriter())
    {
        using (var csv = new CsvWriter(writer))
        {
            csv.WriteRecords(expandos as IEnumerable<dynamic>);
        }

        csvText = writer.ToString();
    }

    Console.WriteLine(csvText);

C# 将 Json 转换为 CSV

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