!1451 add Admin.NET/Admin.NET.Core/Utils/MiniExcelUtil.cs.

Merge pull request !1451 from Hans/N/A

Admin.NET/Admin.NET.Core/Utils/MiniExcelUtil.cs

@@ -0,0 +1,70 @@
+// Admin.NET 项目的版权、商标、专利和其他相关权利均受相应法律法规的保护。使用本项目应遵守相关法律法规和许可证的要求。
+//
+// 本项目主要遵循 MIT 许可证和 Apache 许可证（版本 2.0）进行分发和使用。许可证位于源代码树根目录中的 LICENSE-MIT 和 LICENSE-APACHE 文件。
+//
+// 不得利用本项目从事危害国家安全、扰乱社会秩序、侵犯他人合法权益等法律法规禁止的活动！任何基于本项目二次开发而产生的一切法律纠纷和责任，我们不承担任何责任！
+
+using MiniExcelLibs;
+
+namespace Admin.NET.Core;   
+
+public static class MiniExcelUtil
+{
+    private const string _sheetName = "ImportTemplate";
+    private const string _directory = "export";
+
+    /// <summary>
+    /// 导出模板Excel
+    /// </summary>
+    /// <returns></returns>
+    public static async Task<IActionResult> ExportExcelTemplate<T>(string fileName = null) where T : class, new()
+    {
+        var values = Array.Empty<T>();
+        //在内存中当开辟空间
+        var memoryStream = new MemoryStream();
+        //将数据写到内存当中
+        await memoryStream.SaveAsAsync(values, sheetName: _sheetName);
+        //从0的位置开始写入
+        memoryStream.Seek(0, SeekOrigin.Begin);
+        return new FileStreamResult(memoryStream, "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet")
+        {
+            FileDownloadName = $"{(string.IsNullOrEmpty(fileName) ? typeof(T).Name : fileName)}.xlsx"
+        };
+    }
+
+    /// <summary>
+    /// 获取导入数据Excel
+    /// </summary>
+    /// <param name="file"></param>
+    /// <returns></returns>
+    public static async Task<IEnumerable<T>> GetImportExcelData<T>([Required] IFormFile file) where T : class, new()
+    {
+        using MemoryStream stream = new MemoryStream();
+        await file.CopyToAsync(stream);
+        var res = await stream.QueryAsync<T>(sheetName: _sheetName);
+        return res.ToArray();
+    }
+
+    /// <summary>
+    /// 获取导出数据excel地址
+    /// </summary>
+    /// <returns></returns>
+    public static async Task<string> GetExportDataExcelUrl<T>(IEnumerable<T> exportData) where T : class, new()
+    {
+        var fileName = string.Format("{0}.xlsx", YitIdHelper.NextId());
+        try
+        {
+            var path = Path.Combine(App.WebHostEnvironment.WebRootPath, _directory);
+            if (!Directory.Exists(path))
+                Directory.CreateDirectory(path);
+            var filePath = Path.Combine(path, fileName);
+            await MiniExcel.SaveAsAsync(filePath, exportData, overwriteFile: true);
+        }
+        catch (Exception error)
+        {
+            throw Oops.Oh("出现错误：" + error);
+        }
+        var host = CommonUtil.GetLocalhost();
+        return $"{host}/{_directory}/{fileName}";
+    }
+}