ASP.NET- 使用NPOI导入导出标准Excel

尝试过很多Excel导入导出方法，都不太理想，无意中逛到oschina时，发现了NPOI，无需Office COM组件且不依赖Office，顿时惊为天人，怀着无比激动的心情写下此文。

曾使用过的方法

1. 直接导出html，修改后缀名为.xls，这个方法有点像骗人的把戏，而且不能再导入
2. 使用Jet OLEDB引擎来进行导入导出，完全使用sql语句来进行操作，缺点能控制的东西非常有限，比如格式就难以控制
3. 使用Office COM组件进行导入导出，对环境依赖性太强(如“检索 COM 类工厂…”错误)；且需要通过打开Excel.exe进程进行操作；虽然可以通过关闭工作表以及Marshal.ReleaseComObject方法来释放资源，但依然避免不了性能差。

关于NPOI

NPOI是POI项目的.NET版本，是由@Tony Qu(http://tonyqus.cnblogs.com/)等大侠基于POI开发的，可以从http://npoi.codeplex.com/下载到它的最新版本。它不使用Office COM组件(Microsoft.Office.Interop.XXX.dll)，不需要安装Microsoft Office，支持对Office 97-2003的文件格式，功能比较强大。更详细的说明请看作者的博客或官方网站。

它的以下一些特性让我相当喜欢：

1. 支持对标准的Excel读写
2. 支持对流(Stream)的读写 (而Jet OLEDB和Office COM都只能针对文件)
3. 支持大部分Office COM组件的常用功能
4. 性能优异 (相对于前面的方法)
5. 使用简单，易上手

使用NPOI

本文使用的是它当前的最新版本1.2.4，此版本的程序集缩减至2个：NPOI.dll、Ionic.Zip.dll，直接引用到项目中即可。

对于我们开发者使用的对象主要位于NPOI.HSSF.UserModel空间下，主要有HSSFWorkbook、HSSFSheet、HSSFRow、HSSFCell，对应的接口为位于NPOI.SS.UserModel空间下的IWorkbook、ISheet、IRow、ICell，分别对应Excel文件、工作表、行、列。

简单演示一下创建一个Workbook对象，添加一个工作表，在工作表中添加一行一列：

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using NPOI.HSSF.UserModel; using NPOI.SS.UserModel;    public class NPOIWrite {     void CreateSheet()     {         IWorkbook workbook = new HSSFWorkbook();//创建Workbook对象         ISheet sheet = workbook.CreateSheet("Sheet1");//创建工作表         IRow row = sheet.CreateRow(0);//在工作表中添加一行         ICell cell = row.CreateCell(0);//在行中添加一列         cell.SetCellValue("test");//设置列的内容     } }

相应的读取代码：

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using System.IO; using NPOI.HSSF.UserModel; using NPOI.SS.UserModel;    public class NPOIRead {     void GetSheet(Stream stream)     {         IWorkbook workbook = new HSSFWorkbook(stream);//从流内容创建Workbook对象         ISheet sheet = workbook.GetSheetAt(0);//获取第一个工作表         IRow row = sheet.GetRow(0);//获取工作表第一行         ICell cell = row.GetCell(0);//获取行的第一列         string value = cell.ToString();//获取列的值     } }

使用NPOI导出

从DataTable读取内容来创建Workbook对象：

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public static MemoryStream RenderToExcel(DataTable table) {     MemoryStream ms = new MemoryStream();       using (table)     {         using (IWorkbook workbook = new HSSFWorkbook())         {             using (ISheet sheet = workbook.CreateSheet())             {                 IRow headerRow = sheet.CreateRow(0);                   // handling header.                 foreach (DataColumn column in table.Columns)                     headerRow.CreateCell(column.Ordinal).SetCellValue(column.Caption);//If Caption not set, returns the ColumnName value                   // handling value.                 int rowIndex = 1;                   foreach (DataRow row in table.Rows)                 {                     IRow dataRow = sheet.CreateRow(rowIndex);                       foreach (DataColumn column in table.Columns)                     {                         dataRow.CreateCell(column.Ordinal).SetCellValue(row[column].ToString());                     }                       rowIndex++;                 }                   workbook.Write(ms);                 ms.Flush();                 ms.Position = 0;             }         }     }     return ms; }

如果看不惯DataTable，那么DataReader也行：

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public static MemoryStream RenderToExcel(IDataReader reader) {     MemoryStream ms = new MemoryStream();       using (reader)     {         using (IWorkbook workbook = new HSSFWorkbook())         {             using (ISheet sheet = workbook.CreateSheet())             {                 IRow headerRow = sheet.CreateRow(0);                 int cellCount = reader.FieldCount;                   // handling header.                 for (int i = 0; i < cellCount; i++)                 {                     headerRow.CreateCell(i).SetCellValue(reader.GetName(i));                 }                   // handling value.                 int rowIndex = 1;                 while (reader.Read())                 {                     IRow dataRow = sheet.CreateRow(rowIndex);                       for (int i = 0; i < cellCount; i++)                     {                         dataRow.CreateCell(i).SetCellValue(reader[i].ToString());                     }                       rowIndex++;                 }                   workbook.Write(ms);                 ms.Flush();                 ms.Position = 0;             }         }     }     return ms; }

以上代码把创建的Workbook对象保存到流中，可以通过以下方法输出到浏览器，或是保存到硬盘中：

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static void SaveToFile(MemoryStream ms, string fileName) {     using (FileStream fs = new FileStream(fileName, FileMode.Create, FileAccess.Write))     {         byte[] data = ms.ToArray();           fs.Write(data, 0, data.Length);         fs.Flush();           data = null;     } }   static void RenderToBrowser(MemoryStream ms, HttpContext context, string fileName) {     if (context.Request.Browser.Browser == "IE")         fileName = HttpUtility.UrlEncode(fileName);     context.Response.AddHeader("Content-Disposition", "attachment;fileName=" + fileName);     context.Response.BinaryWrite(ms.ToArray()); }

使用NPOI导入

需要注意的是，sheet.LastRowNum = sheet.PhysicalNumberOfRows - 1，这里可能存在BUG：当没有数据或只有一行数据时sheet.LastRowNum为0，PhysicalNumberOfRows 表现正常。

这里读取流中的Excel来创建Workbook对象，并转换成DataTable：

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static DataTable RenderFromExcel(Stream excelFileStream) {     using (excelFileStream)     {         using (IWorkbook workbook = new HSSFWorkbook(excelFileStream))         {             using (ISheet sheet = workbook.GetSheetAt(0))//取第一个表             {                 DataTable table = new DataTable();                   IRow headerRow = sheet.GetRow(0);//第一行为标题行                 int cellCount = headerRow.LastCellNum;//LastCellNum = PhysicalNumberOfCells                 int rowCount = sheet.LastRowNum;//LastRowNum = PhysicalNumberOfRows - 1                   //handling header.                 for (int i = headerRow.FirstCellNum; i < cellCount; i++)                 {                     DataColumn column = new DataColumn(headerRow.GetCell(i).StringCellValue);                     table.Columns.Add(column);                 }                   for (int i = (sheet.FirstRowNum + 1); i <= rowCount; i++)                 {                     IRow row = sheet.GetRow(i);                     DataRow dataRow = table.NewRow();                       if (row != null)                     {                         for (int j = row.FirstCellNum; j < cellCount; j++)                         {                             if (row.GetCell(j) != null)                                 dataRow[j] = GetCellValue(row.GetCell(j));                         }                     }                       table.Rows.Add(dataRow);                 }                 return table;               }         }     } }

或者是直接生成SQL语句来插入到数据库：

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public static int RenderToDb(Stream excelFileStream, string insertSql, DBAction dbAction) {     int rowAffected = 0;     using (excelFileStream)     {         using (IWorkbook workbook = new HSSFWorkbook(excelFileStream))         {             using (ISheet sheet = workbook.GetSheetAt(0))//取第一个工作表             {                 StringBuilder builder = new StringBuilder();                   IRow headerRow = sheet.GetRow(0);//第一行为标题行                 int cellCount = headerRow.LastCellNum;//LastCellNum = PhysicalNumberOfCells                 int rowCount = sheet.LastRowNum;//LastRowNum = PhysicalNumberOfRows - 1                   for (int i = (sheet.FirstRowNum + 1); i <= rowCount; i++)                 {                     IRow row = sheet.GetRow(i);                     if (row != null)                     {                         builder.Append(insertSql);                         builder.Append(" values (");                         for (int j = row.FirstCellNum; j < cellCount; j++)                         {                             builder.AppendFormat("'{0}',", GetCellValue(row.GetCell(j)).Replace("'", "''"));                         }                         builder.Length = builder.Length - 1;                         builder.Append(");");                     }                       if ((i % 50 == 0 || i == rowCount) && builder.Length > 0)                     {                         //每50条记录一次批量插入到数据库                         rowAffected += dbAction(builder.ToString());                         builder.Length = 0;                     }                 }             }         }     }     return rowAffected; }

这里的Excel可能没有数据，所以可以加一个方法来检测：

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public static bool HasData(Stream excelFileStream) {     using (excelFileStream)     {         using (IWorkbook workbook = new HSSFWorkbook(excelFileStream))         {             if (workbook.NumberOfSheets > 0)             {                 using (ISheet sheet = workbook.GetSheetAt(0))                 {                     return sheet.PhysicalNumberOfRows > 0;                 }             }         }     }     return false; }

 转载自：http://www.cnblogs.com/lwme/archive/2011/11/18/npoi_excel_import_export.html