JSON 字符串到 CSV 和 CSV 到 JSON 在 c# 中的转换

Question

我正在我的 asp.net 网络 API 项目中使用 JSON/CSV 文件并尝试使用 CSVHelper and ServiceStack.Text 库但无法正常工作。

包含数组的JSON文件是动态的，可以有任意数量的字段

我使用 streamreader 读取文件，然后需要将其转换为 CSV 文件以供最终用户下载。

示例文件文本

[{"COLUMN1":"a","COLUMN2":"b","COLUMN3":"c","COLUMN4":"d","COLUMN5":"e"},
 {"COLUMN1":"a","COLUMN2":"b","COLUMN3":"c","COLUMN4":"d","COLUMN5":"e"}]

JSON 到 CSV

public static string jsonStringToCSV(string content)
{
    var jsonContent = (JArray)JsonConvert.DeserializeObject(content);

    var csv = ServiceStack.Text.CsvSerializer.SerializeToCsv(jsonContent);
    return csv;
}

这不会生成 CSV 数据

然后一些文件是带逗号或制表符的分隔符类型，我想利用 CSVHelper 将 CSV 字符串动态转换为 IEnumerable

public static IEnumerable StringToList(string data, string delimiter, bool HasHeader)
{
    using (var csv = new CsvReader(new StringReader(data)))
    {
         csv.Configuration.SkipEmptyRecords = true;
         csv.Configuration.HasHeaderRecord = HasHeader;
         csv.Configuration.Delimiter = delimiter;

         var records = csv.GetRecords();
         return records;
     }
}

Answer 1

我能够使用 Json.net 通过 DeserializeObject 将其解决到数据表，所以想 post 我自己的答案但不会将其标记为已接受，如果有人有更好的方法来做到这一点.

将JSON字符串转换为DataTable

public static DataTable jsonStringToTable(string jsonContent)
        {
            DataTable dt = JsonConvert.DeserializeObject<DataTable>(jsonContent);
            return dt;
        }

制作CSV字符串

public static string jsonToCSV(string jsonContent, string delimiter)
        {
            StringWriter csvString = new StringWriter();
            using (var csv = new CsvWriter(csvString))
            {
                csv.Configuration.SkipEmptyRecords = true;
                csv.Configuration.WillThrowOnMissingField = false;
                csv.Configuration.Delimiter = delimiter;

                using (var dt = jsonStringToTable(jsonContent))
                {
                    foreach (DataColumn column in dt.Columns)
                    {
                        csv.WriteField(column.ColumnName);
                    }
                    csv.NextRecord();

                    foreach (DataRow row in dt.Rows)
                    {
                        for (var i = 0; i < dt.Columns.Count; i++)
                        {
                            csv.WriteField(row[i]);
                        }
                        csv.NextRecord();
                    }
                }
            }
            return csvString.ToString();
        }

Web 中的最终用法 API

string csv = jsonToCSV(content, ",");

                HttpResponseMessage result = new HttpResponseMessage(HttpStatusCode.OK);
                result.Content = new StringContent(csv);
                result.Content.Headers.ContentType = new MediaTypeHeaderValue("text/csv");
                result.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment") { FileName = "export.csv" };
                return result;

Answer 2

public void Convert2Json() 
        { 
            try 
            { 
                if (FileUpload1.PostedFile.FileName != string.Empty) 
                { 
                    string[] FileExt = FileUpload1.FileName.Split('.'); 
                    string FileEx = FileExt[FileExt.Length - 1]; 
                    if (FileEx.ToLower() == "csv") 
                    { 
                        string SourcePath = Server.MapPath("Resources//" + FileUpload1.FileName); 
                        FileUpload1.SaveAs(SourcePath); 
                        string Destpath = (Server.MapPath("Resources//" + FileExt[0] + ".json")); 

                        StreamWriter sw = new StreamWriter(Destpath); 
                        var csv = new List<string[]>(); 
                        var lines = System.IO.File.ReadAllLines(SourcePath); 
                        foreach (string line in lines) 
                            csv.Add(line.Split(',')); 
                        string json = new 
                            System.Web.Script.Serialization.JavaScriptSerializer().Serialize(csv); 
                        sw.Write(json); 
                        sw.Close(); 
                        TextBox1.Text = Destpath; 
                        MessageBox.Show("File is converted to json."); 
                    } 
                    else 
                    { 
                        MessageBox.Show("Invalid File"); 
                    } 

                } 
                else 
                { 
                    MessageBox.Show("File Not Found."); 
                } 
            } 
            catch (Exception ex) 
            { 
                MessageBox.Show(ex.Message); 
            } 
        }

Answer 3

我不知道现在报告您问题的解决方案是否为时已晚。以防万一，如果您想探索开源库来完成这项工作，这里有一个

Cinchoo ETL 只需几行代码即可轻松将 JSON 转换为 csv

using (var r = new ChoJSONReader("sample.json"))
{
    using (var w = new ChoCSVWriter("sample.csv").WithFirstLineHeader())
    {
        w.Write(r);
    }
}

有关更多信息/来源，请转至 https://github.com/Cinchoo/ChoETL

Nuget 包：

.NET 框架:

      Install-Package ChoETL.JSON

.NET 核心:

      Install-Package ChoETL.JSON.NETStandard

示例 fiddle：https://dotnetfiddle.net/T3u4W2

完全披露：我是这个库的作者。

Answer 4

最近遇到了同样的问题，我相信使用 System.Dynamic.ExpandoObject and CsvHelper 有更优雅的解决方案。它的代码更少，并且希望性能与 DataTable 相比相似或更好。

    public static string JsonToCsv(string jsonContent, string delimiter)
    {
        var expandos = JsonConvert.DeserializeObject<ExpandoObject[]>(jsonContent);

        using (var writer = new StringWriter())
        {
            using (var csv = new CsvWriter(writer))
            {
                csv.Configuration.Delimiter = delimiter;

                csv.WriteRecords(expandos as IEnumerable<dynamic>);
            }

            return writer.ToString();
        }
    }

Answer 5

using System.Globalization;

using (var csv = new CsvWriter(csvString, CultureInfo.CurrentCulture)) {
  ...
}

Answer 6

这个代码对我来说没问题：

3 个功能（检查、解析和辅助）

    private bool IsValidJson(string strInput)
    {
        try 
        { 
            if (string.IsNullOrWhiteSpace(strInput)) { return false; }
        
            strInput = strInput.Trim();

            if ((strInput.StartsWith("{") && strInput.EndsWith("}")) || (strInput.StartsWith("[") && strInput.EndsWith("]"))) 
            {
                try
                {
                    _ = JToken.Parse(strInput);

                    return true;
                }
                catch
                {
                    return false;
                }
            }

            return false;
        }
        catch { throw; }
    }

    private string ParseJsonToCsv(string json)
    {
        try
        {
            XmlNode xml = JsonConvert.DeserializeXmlNode("{records:{record:" + json + "}}");

            XmlDocument xmldoc = new XmlDocument(); xmldoc.LoadXml(xml.InnerXml);

            DataSet dataSet = new DataSet(); dataSet.ReadXml(new XmlNodeReader(xmldoc));

            string csv = DTableToCsv(dataSet.Tables[0], ",");

            return csv;
        }
        catch { throw; }
    }

    private string DTableToCsv(DataTable table, string delimator)
    {
        try 
        { 
            var result = new StringBuilder();

            for (int i = 0; i < table.Columns.Count; i++)
            {
                result.Append(table.Columns[i].ColumnName);
                result.Append(i == table.Columns.Count - 1 ? "\n" : delimator);
            }

            foreach (DataRow row in table.Rows)
                for (int i = 0; i < table.Columns.Count; i++)
                {
                    result.Append(row[i].ToString());
                    result.Append(i == table.Columns.Count - 1 ? "\n" : delimator);
                }

            return result.ToString().TrimEnd(new char[] { '\r', '\n' });
        }
        catch { throw; }
    }

JSON 字符串到 CSV 和 CSV 到 JSON 在 c# 中的转换

JSON string to CSV and CSV to JSON conversion in c#

c#

csv

json

csvhelper