Springboot導出文件,前端下載文件方式

 @RequestMapping(value = "/download", method = RequestMethod.POST)
    public void download(HttpServletRequest request, HttpServletResponse res) throws Exception {
        File excelFile = new File("/Users/i501695/GitHUbProject/EN_ProductIntergration/databaseclient/src/main/resources/Files/ProductTemplateCopy.xlsx");
        res.setCharacterEncoding("UTF-8");
        String realFileName = excelFile.getName();
        res.setHeader("content-type", "application/octet-stream;charset=UTF-8");
        res.setContentType("application/octet-stream;charset=UTF-8");
        //加上設置大小下載下來的.xlsx文件打開時才不會報“Excel 已完成文件級驗證和修復。此工作簿的某些部分可能已被修復或丟棄”
        res.addHeader("Content-Length", String.valueOf(excelFile.length()));
        try {
            res.setHeader("Content-Disposition", "attachment;filename=" + java.net.URLEncoder.encode(realFileName.trim(), "UTF-8"));
        } catch (UnsupportedEncodingException e1) {
            e1.printStackTrace();
        }
        byte[] buff = new byte[1024];
        BufferedInputStream bis = null;
        OutputStream os = null;
        try {
            os = res.getOutputStream();
            bis = new BufferedInputStream(new FileInputStream(excelFile));
            int i = bis.read(buff);
            while (i != -1) {
                os.write(buff, 0, buff.length);
                os.flush();
                i = bis.read(buff);
            }
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            if (bis != null) {
                try {
                    bis.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

   Axios({ // 用axios發送post請求
                method: 'post',
                url: 'http://127.0.0.1:8762/dataService/download', // 請求地址
                data: formData, // 參數
                responseType: 'blob' // 表明返回服務器返回的數據類型
            })
                .then((res) => { // 處理返回的文件流
                    let blob = new Blob([res.data], {type: res.data.type})
                    const fileName = 'ProductTemplateCopy.xlsx';
                    let downloadElement = document.createElement('a')
                    let href = window.URL.createObjectURL(blob); //創建下載的鏈接
                    downloadElement.href = href;
                    downloadElement.download = fileName; //下載後文件名
                    document.body.appendChild(downloadElement);
                    downloadElement.click(); //點擊下載
                    document.body.removeChild(downloadElement); //下載完成移除元素
                    window.URL.revokeObjectURL(href); //釋放blob
                    message.success('upload successfully.');
            })
            .catch(function (error) {
                console.log(error);
            });

/**
 * @param path     想要下載的文件的路徑
 * @param response
 * @功能描述 下載文件:
 */
@RequestMapping("/download")
public void download(String path, HttpServletResponse response) {
    try {
        // path是指想要下載的文件的路徑
        File file = new File(path);
        log.info(file.getPath());
        // 獲取文件名
        String filename = file.getName();
        // 獲取文件後綴名
        String ext = filename.substring(filename.lastIndexOf(".") + 1).toLowerCase();
        log.info("文件後綴名：" + ext);
        // 將文件寫入輸入流
        FileInputStream fileInputStream = new FileInputStream(file);
        InputStream fis = new BufferedInputStream(fileInputStream);
        byte[] buffer = new byte[fis.available()];
        fis.read(buffer);
        fis.close();
        // 清空response
        response.reset();
        // 設置response的Header
        response.setCharacterEncoding("UTF-8");
        //Content-Disposition的作用：告知瀏覽器以何種方式顯示響應返回的文件，用瀏覽器打開還是以附件的形式下載到本地保存
        //attachment表示以附件方式下載   inline表示在線打開   "Content-Disposition: inline; filename=文件名.mp3"
        // filename表示文件的默認名稱，因為網絡傳輸隻支持URL編碼的相關支付，因此需要將文件名URL編碼後進行傳輸,前端收到後需要反編碼才能獲取到真正的名稱
        response.addHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(filename, "UTF-8"));
        // 告知瀏覽器文件的大小
        response.addHeader("Content-Length", "" + file.length());
        OutputStream outputStream = new BufferedOutputStream(response.getOutputStream());
        response.setContentType("application/octet-stream");
        outputStream.write(buffer);
        outputStream.flush();
    } catch (IOException ex) {
        ex.printStackTrace();
    }
}

/**
* @param path     指想要下載的文件的路徑
* @param response
* @功能描述 下載文件:將輸入流中的數據循環寫入到響應輸出流中，而不是一次性讀取到內存
*/
@RequestMapping("/downloadLocal")
public void downloadLocal(String path, HttpServletResponse response) throws IOException {
   // 讀到流中
   InputStream inputStream = new FileInputStream(path);// 文件的存放路徑
   response.reset();
   response.setContentType("application/octet-stream");
   String filename = new File(path).getName();
   response.addHeader("Content-Disposition", "attachment; filename=" + URLEncoder.encode(filename, "UTF-8"));
   ServletOutputStream outputStream = response.getOutputStream();
   byte[] b = new byte[1024];
   int len;
   //從輸入流中讀取一定數量的字節，並將其存儲在緩沖區字節數組中，讀到末尾返回-1
   while ((len = inputStream.read(b)) > 0) {
       outputStream.write(b, 0, len);
   }
   inputStream.close();
} 

/**
* @param path       下載後的文件路徑和名稱
* @param netAddress 文件所在網絡地址
* @功能描述 網絡文件下載到服務器本地
*/
@RequestMapping("/netDownloadLocal")
public void downloadNet(String netAddress, String path) throws IOException {
	  URL url = new URL(netAddress);
	  URLConnection conn = url.openConnection();
	  InputStream inputStream = conn.getInputStream();
	  FileOutputStream fileOutputStream = new FileOutputStream(path);
	
	  int bytesum = 0;
	  int byteread;
	  byte[] buffer = new byte[1024];
	  while ((byteread = inputStream.read(buffer)) != -1) {
	      bytesum += byteread;
	      System.out.println(bytesum);
	      fileOutputStream.write(buffer, 0, byteread);
	  }
	  fileOutputStream.close();
}

/**
 * @param netAddress
 * @param filename
 * @param isOnLine
 * @param response
 * @功能描述 網絡文件獲取到服務器後，經服務器處理後響應給前端
 */
@RequestMapping("/netDownLoadNet")
public void netDownLoadNet(String netAddress, String filename, boolean isOnLine, HttpServletResponse response) throws Exception {
    URL url = new URL(netAddress);
    URLConnection conn = url.openConnection();
    InputStream inputStream = conn.getInputStream();
    response.reset();
    response.setContentType(conn.getContentType());
    if (isOnLine) {
        // 在線打開方式 文件名應該編碼成UTF-8
        response.setHeader("Content-Disposition", "inline; filename=" + URLEncoder.encode(filename, "UTF-8"));
    } else {
        //純下載方式 文件名應該編碼成UTF-8
        response.setHeader("Content-Disposition", "attachment; filename=" + URLEncoder.encode(filename, "UTF-8"));
    }
    byte[] buffer = new byte[1024];
    int len;
    OutputStream outputStream = response.getOutputStream();
    while ((len = inputStream.read(buffer)) > 0) {
        outputStream.write(buffer, 0, len);
    }
    inputStream.close();
}

URLEncoder.encode(fileName, "UTF-8")