用NPOI实现导入导出csv、xls、xlsx数据功能

直接上代码

首先定义一个接口

1 public interface ITransferData

2     {

3         Stream GetStream(DataTable table);

4         DataTable GetData(Stream stream);

5     }

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如果需要直接操作文件的话，就自己在封装一次

然后定义csv类的具体实现

public class CsvTransferData : ITransferData

    {

        private Encoding _encode;

        public CsvTransferData()

        {

            this._encode = Encoding.GetEncoding("utf-8");

        }



        public Stream GetStream(DataTable table)

        {

            StringBuilder sb = new StringBuilder();

            if (table != null && table.Columns.Count > 0 && table.Rows.Count > 0)

            {

                foreach (DataRow item in table.Rows)

                {

                    for (int i = 0; i < table.Columns.Count; i++)

                    {

                        if (i > 0)

                        {

                            sb.Append(",");

                        }

                        if (item[i] != null)

                        {

                            sb.Append("\"").Append(item[i].ToString().Replace("\"", "\"\"")).Append("\"");

                        }

                    }

                    sb.Append("\n");

                }

            }

            MemoryStream stream = new MemoryStream(_encode.GetBytes(sb.ToString()));

            return stream;

        }



        public DataTable GetData(Stream stream)

        {

            using (stream)

            {

                using (StreamReader input = new StreamReader(stream, _encode))

                {

                    using (CsvReader csv = new CsvReader(input, false))

                    {

                        DataTable dt = new DataTable();

                        int columnCount = csv.FieldCount;

                        for (int i = 0; i < columnCount; i++)

                        {

                            dt.Columns.Add("col" + i.ToString());

                        }



                        while (csv.ReadNextRecord())

                        {

                            DataRow dr = dt.NewRow();

                            for (int i = 0; i < columnCount; i++)

                            {

                                if (!string.IsNullOrWhiteSpace(csv[i]))

                                {

                                    dr[i] = csv[i];

                                }

                            }

                            dt.Rows.Add(dr);

                        }

                        return dt;

                    }



                }

            }

        }

    }

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这个需要引入命名空间LumenWorks.Framework.IO.Csv;
可以Nuget里面下

接着定义excel的实现类的基类

public abstract class ExcelTransferData : ITransferData

    {

        protected IWorkbook _workBook;



        public virtual Stream GetStream(DataTable table)

        {

            var sheet = _workBook.CreateSheet();

            if (table != null)

            {

                var rowCount = table.Rows.Count;

                for (int i = 0; i < table.Rows.Count; i++)

                {

                    var row = sheet.CreateRow(i);

                    for (int j = 0; j < table.Columns.Count; j++)

                    {

                        var cell = row.CreateCell(j);

                        if (table.Rows[i][j] != null)

                        {

                            cell.SetCellValue(table.Rows[i][j].ToString());

                        }

                    }

                }

            }            

            MemoryStream ms = new MemoryStream();

            _workBook.Write(ms);

            return ms;

        }



        public virtual DataTable GetData(Stream stream)

        {

            using (stream)

            {

                var sheet = _workBook.GetSheetAt(0);

                if (sheet != null)

                {

                    var headerRow = sheet.GetRow(0);

                    DataTable dt = new DataTable();

                    int columnCount = headerRow.Cells.Count;

                    for (int i = 0; i < columnCount; i++)

                    {

                        dt.Columns.Add("col_" + i.ToString());

                    }

                    var row = sheet.GetRowEnumerator();

                    while (row.MoveNext())

                    {

                        var dtRow = dt.NewRow();

                        var excelRow = row.Current as IRow;

                        for (int i = 0; i < columnCount; i++)

                        {

                            var cell = excelRow.GetCell(i);



                            if (cell != null)

                            {

                                dtRow[i] = GetValue(cell);

                            }

                        }

                        dt.Rows.Add(dtRow);

                    }

                    return dt;

                }

            }



            return null;

        }





        private object GetValue(ICell cell)

        {

            object value = null;

            switch (cell.CellType)

            {

                case CellType.BLANK:

                    break;

                case CellType.BOOLEAN:

                    value = cell.BooleanCellValue ? "1" : "0"; break;

                case CellType.ERROR:

                    value = cell.ErrorCellValue; break;

                case CellType.FORMULA:

                    value = "=" + cell.CellFormula; break;

                case CellType.NUMERIC:

                    value = cell.NumericCellValue.ToString(); break;

                case CellType.STRING:

                    value = cell.StringCellValue; break;

                case CellType.Unknown:

                    break;

            }

            return value;

        }



    }

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这个需要下载NPOI 2.01版本 

下载地址http://npoi.codeplex.com/releases/view/92382

接着实现2003版本

public class XlsTransferData : ExcelTransferData

    {

        public override Stream GetStream(DataTable table)

        {

            base._workBook = new HSSFWorkbook();

            return base.GetStream(table);

        }



        public override DataTable GetData(Stream stream)

        {

            base._workBook = new HSSFWorkbook(stream);

            return base.GetData(stream);

        }

    }

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接着实现2007版本

public class XlsxTransferData : ExcelTransferData

    {



        public override Stream GetStream(DataTable table)

        {

            base._workBook = new XSSFWorkbook();

            return base.GetStream(table);

        }



        public override DataTable GetData(Stream stream)

        {

            base._workBook = new XSSFWorkbook(stream);

            return base.GetData(stream);

        }

    }

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然后定义一个枚举实现一个简单的工厂

public enum DataFileType

    {

        CSV,

        XLS,

        XLSX

    }



    public class TransferDataFactory

    {

        public static ITransferData GetUtil(string fileName)

        {

            var array = fileName.Split('.');

            var dataType = (DataFileType)Enum.Parse(typeof(DataFileType), array[array.Length - 1], true);

            return GetUtil(dataType);

        }



        public static ITransferData GetUtil(DataFileType dataType)

        {

            switch (dataType)

            {

                case DataFileType.CSV: return new CsvTransferData();

                case DataFileType.XLS: return new XlsTransferData();

                case DataFileType.XLSX: return new XlsxTransferData();

                default: return new CsvTransferData();

            }

        }



    }

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客户端调用代码

class Program

    {

        static void Main(string[] args)

        {

            var fileName = @"C:/Users/ranrx/Desktop/data.xlsx";

            FileStream stream = new FileStream(fileName, FileMode.Open, FileAccess.Read);

            var util = TransferDataFactory.GetUtil(fileName);

            var data = util.GetData(stream);

            var mStream = util.GetStream(data);         



        }

    }

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