.net webapi导出excel

public IActionResult downloadWeeklyTemplate()
        {


            string basePath = AppDomain.CurrentDomain.BaseDirectory;
            string path = basePath + "/excel.xlsx";

            var f = new FileInfo(path);
            if (!f.Exists)
            {

                return BadRequest("未找到文件");
            }

            var contentType = "application/octet-stream";

            byte[] buffer = new byte[f.Length];

            using (FileStream stream = f.OpenRead())
            {
                stream.Read(buffer, 0, buffer.Length);
            }

           

            return File(buffer, contentType, "excel.xlsx"); }

2.如果是后台查询数据并生成excel导出那么需要MemoryStream读取字节，代码如下

  XSSFWorkbook wookBook = //这边是使用NPOI生成的对象，自己填充数据;byte[] buffer;

            using (MemoryStream ms = new MemoryStream())
            {
                wookBook.Write(ms);
                //ms.Flush();
                //ms.Position=0;
                //ms.Flush();
                buffer = ms.ToArray();
                ms.Close();
            }

3. 前端请求使用axios,并且将responseType 设置成"bolb",否则会出现下载后文件已损坏的情况。

 axios.post(Apiurl, params, {
           
            responseType: 'blob'
        })
            .then(res => {
                    const blob = new Blob([res.data])
                    const fileName = 'excel.xlsx'

                    const elink = document.createElement('a')
                    elink.download = fileName
                    elink.style.display = 'none'
                    elink.href = URL.createObjectURL(blob)
                    elink.setAttribute('download', 'excel.xlsx')
                    document.body.appendChild(elink)
                    elink.click()
                    URL.revokeObjectURL(elink.href) // 释放URL 对象
                    document.body.removeChild(elink)

            })
            .catch(err => {
                reject(err.data)
            })