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

public interface ITransferData
    {
        Stream GetStream(DataTable table);
        DataTable GetData(Stream stream);
    }

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;
                    }

                }
            }
        }
    }

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;
        }

    }

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);
        }
    }

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);
        }
    }

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();
            }
        }

    }

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);         

        }
    }