NPOI从数据库中调取数据直接导出到EXCEL中
https://blog.csdn.net/weixin_30725315/article/details/98769248
一、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：
支持对标准的Excel读写
支持对流(Stream)的读写 (而Jet OLEDB和Office COM都只能针对文件)
支持大部分Office COM组件的常用功能
性能优异 (相对于前面的方法)
使用简单，易上手
二、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：
操作示例代码：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.IO;
using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;
using System.Data;
using System.Data.SqlClient;
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
MemoryStream ms = RenderToExcel(GetTable());
string fileName = @"c:\2.xls";
SaveToFile(ms, fileName);
Response.Write("成功");
}
public MemoryStream RenderToExcel(DataTable table)
{
MemoryStream ms = new MemoryStream();
using (table)
{
IWorkbook workbook = new HSSFWorkbook();
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;
}
private 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;
}
}
private DataTable GetTable()
{
SqlHelperXhf xhf = new SqlHelperXhf();
string sql = "select calling_no '电话号码',starttime '时间' ,hname '楼盘名称' from [fc_freetel] a where hname<>'无'and a.id = (select min(id) from fc_freetel where calling_no=a.calling_no) order by hname,starttime desc";
return xhf.ExecuteDataTable(sql);
}
private DataTable GetTable(int hid)
{
SqlHelperXhf xhf = new SqlHelperXhf();
string sql = "select calling_no '电话号码',starttime '时间' ,hname '楼盘名称' from [fc_freetel] a where hid=@hid and a.id = (select min(id) from fc_freetel where calling_no=a.calling_no) order by hname,starttime desc";
SqlParameter paramer = new SqlParameter("@hid", hid);
return xhf.ExecuteDataTable(sql,paramer);
}
private DataTable GetTable(int hid1,int hid2,int hid3)
{
SqlHelperXhf xhf = new SqlHelperXhf();
string sql = "select calling_no '电话号码',starttime '时间' ,hname '楼盘名称' from [fc_freetel] a where hid=@hid1 or hid=@hid2 or hid=@hid3 and a.id = (select min(id) from fc_freetel where calling_no=a.calling_no) order by hname,starttime desc";
SqlParameter [] paramers =
{
new SqlParameter("@hid1", hid1),
new SqlParameter("@hid2", hid2),
new SqlParameter("@hid3", hid3)
};
return xhf.ExecuteDataTable(sql, paramers);
}
}参考资料：
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：
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：
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
}
}
三、使用NPOI导出
从DataTable读取内容来创建Workbook对象：
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：
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：
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());
}四、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：
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：
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：
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;
}转载于:https://www.cnblogs.com/xuhongfei/p/3159018.html
https://blog.csdn.net/weixin_30725315/article/details/98769248