Apache POI -如何在Grails应用程序中提供用于下载的excel文件

compile 'org.apache.poi:poi:4.1.2'
compile 'org.apache.poi:poi-ooxml:4.1.2'

import org.apache.poi.ss.usermodel.*
import org.apache.poi.xssf.usermodel.XSSFWorkbook

class ExcelService {
    Workbook createExcel() {
        Workbook workbook = new XSSFWorkbook()
        Sheet sheet = workbook.createSheet("Sheet1")

        // 创建标题行
        Row headerRow = sheet.createRow(0)
        headerRow.createCell(0).setCellValue("姓名")
        headerRow.createCell(1).setCellValue("年龄")

        // 创建数据行
        Row dataRow = sheet.createRow(1)
        dataRow.createCell(0).setCellValue("张三")
        dataRow.createCell(1).setCellValue(25)

        return workbook
    }
}

import grails.plugin.springsecurity.annotation.Secured

class ExcelController {
    @Secured(['ROLE_USER'])
    def downloadExcel() {
        ExcelService excelService = new ExcelService()
        Workbook workbook = excelService.createExcel()

        response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet")
        response.setHeader("Content-disposition", "attachment; filename=example.xlsx")

        workbook.write(response.outputStream)
        workbook.close()
        response.outputStream.flush()
    }
}