Github : https://github.com/shps951023/MiniExcel
简介
我尝试做一个.NET简单、高效、避免OOM的Excel工具
目前主流框架大多将资料全载入到记忆体方便操作，但这会导致记忆体消耗问题，MiniExcel 尝试以 Stream 角度写底层算法逻辑，能让原本1000多MB占用降低到几MB，避免记忆体不够情况。适合像是低规格 azure app service 或是读取大档案等情境。
特点
- 低内存耗用，避免OOM(out of memoery)、频繁 Full GC 情况
- 支持
即时操作每行数据
- 兼具搭配 LINQ 延迟查询特性，能办到低消耗、快速分页等复杂查询
图片:与主流框架对比的消耗、效率差
- 轻量，不依赖任何套件，DLL小于100KB
- 简便操作的 Dapper API 风格
安装
请查看 from NuGet
更新日志
请查看 Release Notes
TODO
请查看 Project · todo
性能测试
以 Test1,000,000x10.xlsx 做基准与主流框架做性能测试，总共 1千万笔 "HelloWorld"，文件大小 23 MB
Benchmarks 逻辑可以在 MiniExcel.Benchmarks 查看或是提交 PR，运行指令
dotnet run -p .\benchmarks\MiniExcel.Benchmarks\ -c Release -f netcoreapp3.1 -- -f * --join
最后一次运行结果 :
BenchmarkDotNet=v0.12.1, OS=Windows 10.0.19042
Intel Core i7-7700 CPU 3.60GHz (Kaby Lake), 1 CPU, 8 logical and 4 physical cores
[Host] : .NET Framework 4.8 (4.8.4341.0), X64 RyuJIT
Job-ZYYABG : .NET Framework 4.8 (4.8.4341.0), X64 RyuJIT
IterationCount=3 LaunchCount=3 WarmupCount=3
| Method | 最大内存耗用 | 平均时间 | Gen 0 | Gen 1 | Gen 2 |
|---|---|---|---|---|---|
| 'MiniExcel QueryFirst' | 0.109 MB | 726.4 us | - | - | - |
| 'ExcelDataReader QueryFirst' | 15.24 MB | 10,664,238.2 us | 566000.0000 | 1000.0000 | - |
| 'MiniExcel Query' | 17.3 MB | 14,179,334.8 us | 367000.0000 | 96000.0000 | 7000.0000 |
| 'ExcelDataReader Query' | 17.3 MB | 22,565,088.7 us | 1210000.0000 | 2000.0000 | - |
| 'Epplus QueryFirst' | 1,452 MB | 18,198,015.4 us | 535000.0000 | 132000.0000 | 9000.0000 |
| 'Epplus Query' | 1,451 MB | 23,647,471.1 us | 1451000.0000 | 133000.0000 | 9000.0000 |
| 'OpenXmlSDK Query' | 1,412 MB | 52,003,270.1 us | 978000.0000 | 353000.0000 | 11000.0000 |
| 'OpenXmlSDK QueryFirst' | 1,413 MB | 52,348,659.1 us | 978000.0000 | 353000.0000 | 11000.0000 |
| 'ClosedXml QueryFirst' | 2,158 MB | 66,188,979.6 us | 2156000.0000 | 575000.0000 | 9000.0000 |
| 'ClosedXml Query' | 2,184 MB | 191,434,126.6 us | 2165000.0000 | 577000.0000 | 10000.0000 |
| Method | 最大内存耗用 | 平均时间 | Gen 0 | Gen 1 | Gen 2 |
|---|---|---|---|---|---|
| 'MiniExcel Create Xlsx' | 15 MB | 11,531,819.8 us | 1020000.0000 | - | - |
| 'Epplus Create Xlsx' | 1,204 MB | 22,509,717.7 us | 1370000.0000 | 60000.0000 | 30000.0000 |
| 'OpenXmlSdk Create Xlsx' | 2,621 MB | 42,473,998.9 us | 1370000.0000 | 460000.0000 | 50000.0000 |
| 'ClosedXml Create Xlsx' | 7,141 MB | 140,939,928.6 us | 5520000.0000 | 1500000.0000 | 80000.0000 |
Query 查询 Excel 返回强型别 IEnumerable 数据 [Try it]
推荐使用 Stream.Query 效率会相对较好。
public class UserAccount
{
public Guid ID { get; set; }
public string Name { get; set; }
public DateTime BoD { get; set; }
public int Age { get; set; }
public bool VIP { get; set; }
public decimal Points { get; set; }
}
var rows = MiniExcel.Query<UserAccount>(path);
// or
using (var stream = File.OpenRead(path))
var rows = stream.Query<UserAccount>();
Query 查询 Excel 返回Dynamic IEnumerable 数据 [Try it]
- Key 系统预设为
A,B,C,D...Z
| MiniExcel | 1 |
|---|---|
| Github | 2 |
var rows = MiniExcel.Query(path).ToList();
// or
using (var stream = File.OpenRead(path))
{
var rows = stream.Query().ToList();
Assert.Equal("MiniExcel", rows[0].A);
Assert.Equal(1, rows[0].B);
Assert.Equal("Github", rows[1].A);
Assert.Equal(2, rows[1].B);
}
查询数据以第一行数据当Key [Try it]
note : 同名以右边数据为准
Input Excel :
| Column1 | Column2 |
|---|---|
| MiniExcel | 1 |
| Github | 2 |
var rows = MiniExcel.Query(useHeaderRow:true).ToList();
// or
using (var stream = File.OpenRead(path))
{
var rows = stream.Query(useHeaderRow:true).ToList();
Assert.Equal("MiniExcel", rows[0].Column1);
Assert.Equal(1, rows[0].Column2);
Assert.Equal("Github", rows[1].Column1);
Assert.Equal(2, rows[1].Column2);
}
Query 查询支援延迟加载(Deferred Execution)，能配合LINQ First/Take/Skip办到低消耗、高效率复杂查询
Query First
var row = MiniExcel.Query(path).First();
Assert.Equal("HelloWorld", row.A);
// or
using (var stream = File.OpenRead(path))
{
var row = stream.Query().First();
Assert.Equal("HelloWorld", row.A);
}
建立 Excel 文件 [Try it]
- 必须是 non-abstract 类别有 public parameterless constructor
- MiniExcel SaveAs 支援
IEnumerable参数``延迟查询，除非必要请不要使用 ToList 等方法读取全部数据到内存
图片 : 是否呼叫 ToList 的内存差别
Anonymous or strongly type:
var path = Path.Combine(Path.GetTempPath(), $"{Guid.NewGuid()}.xlsx");
MiniExcel.SaveAs(path, new[] {
new { Column1 = "MiniExcel", Column2 = 1 },
new { Column1 = "Github", Column2 = 2}
});
Datatable:
var path = Path.Combine(Path.GetTempPath(), $"{Guid.NewGuid()}.xlsx");
var table = new DataTable();
{
table.Columns.Add("Column1", typeof(string));
table.Columns.Add("Column2", typeof(decimal));
table.Rows.Add("MiniExcel", 1);
table.Rows.Add("Github", 2);
}
MiniExcel.SaveAs(path, table);
Dapper:
using (var connection = GetConnection(connectionString))
{
var rows = connection.Query(@"select 'MiniExcel' as Column1,1 as Column2 union all select 'Github',2");
MiniExcel.SaveAs(path, rows);
}
IEnumerable<IDictionary<string, object>>
var values = new List<Dictionary<string, object>>()
{
new Dictionary<string,object>{{ "Column1", "MiniExcel" }, { "Column2", 1 } },
new Dictionary<string,object>{{ "Column1", "Github" }, { "Column2", 2 } }
};
MiniExcel.SaveAs(path, values);
output :
| Column1 | Column2 |
|---|---|
| MiniExcel | 1 |
| Github | 2 |
SaveAs 支援 Stream [Try it]
using (var stream = File.Create(path))
{
stream.SaveAs(values);
}
Excel Column Name/Ignore Attribute
e.g
input excel :
| Test1 | Test2 | Test3 | Test4 | Test5 | Test6 | Column1 | Column2 |
|---|---|---|---|---|---|---|---|
| Test1 | Test2 | Test3 | Test4 | Test5 | Test6 | Column1 | Column2 |
public class ExcelAttributeDemo
{
[ExcelColumnName("Column1")]
public string Test1 { get; set; }
[ExcelColumnName("Column2")]
public string Test2 { get; set; }
[ExcelIgnore]
public string Test3 { get; set; }
public string Test4 { get; set; }
public string Test5 { get; }
public string Test6 { get; private set; }
}
var rows = MiniExcel.Query<ExcelAttributeDemo>(path).ToList();
Assert.Equal("Column1", rows[0].Test1);
Assert.Equal("Column2", rows[0].Test2);
Assert.Null(rows[0].Test3);
Assert.Equal("Test4", rows[0].Test4);
Assert.Null(rows[0].Test5);
Assert.Null(rows[0].Test6);
例子 : SQLite & Dapper 读取大数据新增到数据库
note : 请不要呼叫 call ToList/ToArray 等方法，这会将所有数据读到内存内
using (var connection = new SQLiteConnection(connectionString))
{
connection.Open();
using (var transaction = connection.BeginTransaction())
using (var stream = File.OpenRead(path))
{
var rows = stream.Query();
foreach (var row in rows)
connection.Execute("insert into T (A,B) values (@A,@B)", new { row.A, row.B }, transaction: transaction);
transaction.Commit();
}
}
效能:
例子 : ASP.NET Core 3.1 or MVC 5 下载 Excel Xlsx API Demo
public class ExcelController : Controller
{
public IActionResult Download()
{
var values = new[] {
new { Column1 = "MiniExcel", Column2 = 1 },
new { Column1 = "Github", Column2 = 2}
};
var stream = new MemoryStream();
stream.SaveAs(values);
return File(stream,
"application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
"demo.xlsx");
}
}
Excel 类别自动判断
MiniExcel 预设会根据扩展名或是 Stream 类别判断是 xlsx 还是 csv，但会有失准时候，请自行指定。
stream.SaveAs(excelType:ExcelType.CSV);
//or
stream.SaveAs(excelType:ExcelType.XLSX);
//or
stream.Query(excelType:ExcelType.CSV);
//or
stream.Query(excelType:ExcelType.XLSX);
Dynamic Query 转换 IDictionary<string,object> 数据
foreach(IDictionary<string,object> row = MiniExcel.Query(path))
{
//..
}
局限与警告
- 目前不支援 xls (97-2003) 或是加密文件。
- 不支援样式、字体、宽度等
修改，因为 MiniExcel 概念是只专注于值数据，借此降低内存消耗跟提升效率。
参考
- 读取逻辑 : ExcelDataReader
- API 设计方式 : StackExchange/Dapper