c# NPOI 匯出23萬條記錄耗時12秒
阿新 • • 發佈：2019-08-18
先上測試程式碼:
string connectionString = "Server=localhost;Initial Catalog=******;User ID=sa;Password=******;";
List<TestData> datas = null;
using (SqlConnection db = new SqlConnection(connectionString))
{
datas = db.Query<TestData>("SELECT * FROM TestData").ToList();
}
System.Console.WriteLine($"資料來源物件 {typeof(TestData).GetProperties().Length} 個欄位,共 {datas.Count} 條記錄,大小 {BinarySerializeHelper.SerializeToBytes(datas).Length/1000/1000} M");
Task.Run(() =>
{
while (true)
{
System.Console.WriteLine($"{DateTime.Now} 記憶體 : {GC.GetTotalMemory(false) / 1000 / 1000} M");
Thread.Sleep(1000);
}
});
Stopwatch sw = new Stopwatch();
sw.Start();
byte[] bytes = ExcelHandlerFactory.CreateHandler(datas).CreateExcelBytes();
sw.Stop();
System.Console.WriteLine($"{DateTime.Now} 資料來源轉Excel檔案位元組陣列耗時 : "+sw.ElapsedMilliseconds / 1000 +" 秒");
string path = @"C:\Users\Administrator\Desktop\1.xlsx";
FileStream fs = new FileStream(path, FileMode.OpenOrCreate, FileAccess.Write);
fs.Write(bytes);
fs.Dispose();
System.Console.ReadKey();
測試結果:
就是這記憶體佔用有點高......
原始碼:
using System.Collections.Generic;
namespace Wjire.Excel
{
/// <summary>
/// ExcelHandler工廠
/// </summary>
public static class ExcelHandlerFactory
{
/// <summary>
/// 建立ExcelHandler
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="sources">資料來源</param>
/// <param name="choosedFields">需要匯出的欄位,可不傳,則匯出所有欄位</param>
/// <returns></returns>
public static ExcelHandler<T> CreateHandler<T>(IEnumerable<T> sources, HashSet<string> choosedFields = null)
{
return new ExcelHandler<T>(sources, choosedFields);
}
}
}using NPOI.HSSF.UserModel;
using NPOI.SS.UserModel;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
namespace Wjire.Excel
{
/// <summary>
/// 報表匯出處理者
/// </summary>
public sealed class ExcelHandler<TSource>
{
/// <summary>
/// 資料來源
/// </summary>
private readonly IEnumerable<TSource> _sources;
/// <summary>
/// 需要匯出的列資訊
/// </summary>
private readonly ColumnInfo[] _columnInfos;
/// <summary>
/// 工作簿
/// </summary>
private IWorkbook _workbook;
/// <summary>
/// 工作頁
/// </summary>
private ISheet _sheet;
/// <summary>
/// 單元格樣式
/// </summary>
private ICellStyle _cellStyle;
/// <summary>
/// 單元格樣式提供器
/// </summary>
private ICellStyleProvider _provider;
internal ExcelHandler(IEnumerable<TSource> sources, HashSet<string> choosedFields)
{
_sources = sources;
_columnInfos = GetColumnInfosOfExport(choosedFields);
}
/// <summary>
/// 資料來源轉位元組
/// </summary>
/// <returns></returns>
public byte[] CreateExcelBytes()
{
using (var ms = CreateExcelStream())
{
return ms.ToArray();
}
}
/// <summary>
/// 資料來源轉excel流
/// </summary>
/// <returns></returns>
public MemoryStream CreateExcelStream()
{
try
{
_workbook = new HSSFWorkbook();
_cellStyle = (_provider ?? DefaultCellStyleProvider.Singleton.Value).CreateCellStyle(_workbook);
int sheetIndex = 1;
CreateSheetWithHeader(sheetIndex);
int rowIndex = 1;
foreach (TSource entity in _sources)
{
//03版 excel 一個 _sheet 最多 65535 行
if (rowIndex == 65535)
{
sheetIndex++;
CreateSheetWithHeader(sheetIndex);
rowIndex = 1;
}
CreateDataRow(rowIndex, entity);
rowIndex++;
}
MemoryStream ms = new MemoryStream();
_workbook.Write(ms);
return ms;
}
finally
{
_workbook?.Close();
}
}
/// <summary>
/// 建立Sheet及列頭
/// </summary>
private void CreateSheetWithHeader(int sheetIndex)
{
_sheet = _workbook.CreateSheet("第 " + sheetIndex + " 頁");
//凍結首行首列
_sheet.CreateFreezePane(0, 1);
IRow header = _sheet.CreateRow(0);
for (int i = 0; i < _columnInfos.Length; i++)
{
ICell cell = header.CreateCell(i);
cell.SetCellValue(_columnInfos[i].CellDisplayAttribute.Name);
cell.CellStyle = _cellStyle;
//自適應寬度
_sheet.AutoSizeColumn(i);
}
}
/// <summary>
/// 建立資料行
/// </summary>
/// <param name="rowIndex">行索引</param>
/// <param name="entity">資料</param>
private void CreateDataRow(int rowIndex, object entity)
{
IRow dataRow = _sheet.CreateRow(rowIndex);
for (int i = 0; i < _columnInfos.Length; i++)
{
ICell cell = dataRow.CreateCell(i);
cell.CellStyle = _cellStyle;
object value = _columnInfos[i].PropertyInfo.GetValue(entity, null);
SetCellValue(value, cell);
}
}
/// <summary>
/// 設定單元格值
/// </summary>
/// <param name="value"></param>
/// <param name="cell"></param>
private void SetCellValue(object value, ICell cell)
{
if (value == null)
{
cell.SetCellValue(string.Empty);
return;
}
Type type = value.GetType();
switch (type.Name)
{
case "DateTime":
case "String":
case "Boolean":
cell.SetCellValue(value.ToString());
break;
case "Byte":
case "Int16":
case "Int32":
case "Int64":
case "Single":
case "Double":
case "Decimal":
cell.SetCellValue(Convert.ToDouble(value));
break;
default:
cell.SetCellValue(string.Empty);
break;
}
}
/// <summary>
/// 設定excel單元格樣式提供器
/// </summary>
/// <param name="provider"></param>
/// <returns></returns>
public ExcelHandler<TSource> SetCellStyleProvider(ICellStyleProvider provider)
{
_provider = provider;
return this;
}
/// <summary>
/// 獲取需要匯出的列資訊
/// </summary>
/// <param name="choosedFields"></param>
/// <returns></returns>
private ColumnInfo[] GetColumnInfosOfExport(HashSet<string> choosedFields)
{
ColumnInfo[] columnInfos = ColumnInfoContainer.GetColumnInfo(typeof(TSource));
return choosedFields?.Count > 0
? columnInfos.Where(w => choosedFields.Contains(w.PropertyInfo.Name)).ToArray()
: columnInfos;
}
}
}using System.Reflection;
namespace Wjire.Excel
{
/// <summary>
/// 列資訊
/// </summary>
public class ColumnInfo
{
internal PropertyInfo PropertyInfo { get; set; }
internal CellDisplayAttribute CellDisplayAttribute { get; set; }
}
}
View Code
using System;
namespace Wjire.Excel
{
/// <summary>
/// excel 單元格資料顯示自定義特性類
/// </summary>
[AttributeUsage(AttributeTargets.Property)]
public sealed class CellDisplayAttribute : Attribute
{
/// <summary>
/// 自定義列名
/// </summary>
public string Name { get; set; }
/// <summary>
/// 建構函式
/// </summary>
/// <param name="name">自定義列名</param>
public CellDisplayAttribute(string name)
{
Name = name;
}
}
}
View Code
using NPOI.SS.UserModel;
namespace Wjire.Excel
{
/// <summary>
/// 單元格樣式提供器介面
/// </summary>
public interface ICellStyleProvider
{
ICellStyle CreateCellStyle(IWorkbook workbook);
}
}
View Code
using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
namespace Wjire.Excel
{
/// <summary>
/// 資料來源列資訊容器
/// </summary>
internal static class ColumnInfoContainer
{
private static readonly Dictionary<Type, ColumnInfo[]> Container = new Dictionary<Type, ColumnInfo[]>();
/// <summary>
/// 獲取資料來源列資訊
/// </summary>
/// <param name="sourceType">資料來源類型別</param>
/// <returns></returns>
internal static ColumnInfo[] GetColumnInfo(Type sourceType)
{
if (Container.TryGetValue(sourceType, out ColumnInfo[] infos))
{
return infos;
}
infos = sourceType
.GetProperties(BindingFlags.Public | BindingFlags.Instance)
.Where(propertyInfo => propertyInfo.GetCustomAttribute<CellDisplayAttribute>(true) != null)
.Select(propertyInfo => new ColumnInfo
{
PropertyInfo = propertyInfo,
CellDisplayAttribute = propertyInfo.GetCustomAttribute<CellDisplayAttribute>()
}).ToArray();
Container.Add(sourceType, infos);
return infos;
}
}
}
View Code
using NPOI.SS.UserModel;
using System;
namespace Wjire.Excel
{
/// <summary>
/// 預設單元格樣式提供器
/// </summary>
internal class DefaultCellStyleProvider : ICellStyleProvider
{
internal static Lazy<DefaultCellStyleProvider> Singleton = new Lazy<DefaultCellStyleProvider>(() => new DefaultCellStyleProvider());
private DefaultCellStyleProvider()
{
}
/// <summary>
/// 建立單元格樣式
/// </summary>
/// <param name="workbook"></param>
/// <returns></returns>
public ICellStyle CreateCellStyle(IWorkbook workbook)
{
ICellStyle cellStyle = workbook.CreateCellStyle();
cellStyle.Alignment = HorizontalAlignment.Center;
//cellStyle.VerticalAlignment = VerticalAlignment.Center;//垂直居中非常影響效率,不建議開啟該功能
IFont font = workbook.CreateFont();
font.FontHeightInPoints = 11;
//font.Boldweight = 700;
cellStyle.SetFont(font);
//邊框
//cellStyle.BorderBottom = BorderStyle.Thin;
//cellStyle.BorderLeft = BorderStyle.Thin;
//cellStyle.BorderRight = BorderStyle.Thin;
//cellStyle.BorderTop = BorderStyle.Thin;
return cellStyle;
}
}
}
View Code
幾點說明:
1.NPOI 用的最新版本:2.4.1;
2.程式碼中用的 HSSFWorkbook ,不僅僅是為了相容 word2003,在測試的時候發現,如果用 XSSFWorkbook ,耗時慢了N個數量級,不知道是不是哪裡姿勢不對;
3.單元格的寬度只在標題欄設定了,所以匯出來的Excel可能比較醜.原因是:
1)如果根據單元格內容的長度來調整的話,由於每一個單元格內容的長度都肯能不一樣,太耗時,沒必要,不如滑鼠點兩下來得快;
2)雖然NPOI有個功能可以在一個sheet的資料填充完後,設定單元格的寬度自適應,但是測試了下,太太太太慢了.估計是在遍歷所有的單元格,一個一個計算;
3)還有一個折中的辦法,就是根據第一行資料的各個單元格內容來調整寬度,因為有些時候,資料物件每個屬性的值的長度都不會差太多.但是當長度不一的時候,會讓人誤以為那些長的單元格的內容已經顯示完了,所以也捨棄了這個功能.
4.測試的時候發現,如果把某一列的單元格設定成超連結,點選可以開啟瀏覽器檢視那種,非常非常非常非常慢.慘不忍睹.不知道是不是姿勢不對,所以也捨棄了該功