调整项目架构,让框架更优化

excel/excel.go

@@ -87,9 +87,12 @@ type ExportData interface {
 //
 //	excel.ExportToWriter(w, "用户列表", columns, users)
 func (e *Excel) ExportToWriter(w io.Writer, sheetName string, columns []ExportColumn, data interface{}) error {
-	if e.file == nil {
-		e.file = excelize.NewFile()
-	}
+	// 每次导出使用新文件，避免同实例多次/并发导出互相污染
+	e.file = excelize.NewFile()
+	defer func() {
+		_ = e.file.Close()
+		e.file = nil
+	}()
 
 	// 设置工作表名称
 	if sheetName == "" {

excel/excel_test.go

@@ -0,0 +1,35 @@
+package excel
+
+import (
+	"bytes"
+	"testing"
+)
+
+type row struct {
+	ID   int
+	Name string
+}
+
+func TestExportToWriterResetsFile(t *testing.T) {
+	ex := NewExcel()
+	cols := []ExportColumn{
+		{Header: "ID", Field: "ID"},
+		{Header: "Name", Field: "Name"},
+	}
+	data := []row{{ID: 1, Name: "a"}, {ID: 2, Name: "b"}}
+
+	var buf1, buf2 bytes.Buffer
+	if err := ex.ExportToWriter(&buf1, "S1", cols, data); err != nil {
+		t.Fatal(err)
+	}
+	if err := ex.ExportToWriter(&buf2, "S1", cols, data); err != nil {
+		t.Fatal(err)
+	}
+	if buf1.Len() == 0 || buf2.Len() == 0 {
+		t.Fatal("expected non-empty xlsx output")
+	}
+	// 导出后不应残留内部文件句柄
+	if ex.file != nil {
+		t.Fatal("internal file should be cleared after ExportToWriter")
+	}
+}