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。我怎样才能在C＃中实现这个目标？

注意，作为一个例子，我在“PKTDTL”中只有3个项目，真正的json文件有数千行（{“SRNO”...}）并且很大。

我写了下面的代码但是没有用。请参阅代码中注释的错误消息。

问题

任何人都知道失败的原因？

你有更好的/替代方法

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。这就是我做的。首先我创建了一个JObject（使用Newtonsoft.Json.Linq），让我们考虑一下你的json是一个名为“strJSON”的字符串变量。

 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保存为csv

Answer 2

使用Cinchoo ETL - 一个开源库，您可以使用几行代码轻松完成转换

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

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Answer 3

与duplicate类似的问题（请参见那里的JsonToCsv（string，string）方法）。如果您已经在使用NewtonSoft Json.NET和CsvHelper，则可以在ExpandoObject的帮助下进行类似的转换。

    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

3 个答案: