SpringBoot實現檔案下載功能的方式分享

/**
 * @param path     想要下載的檔案的路徑
 * @param response
 * @功能描述 下載檔案:
 */
@RequestMapping("/download")
public void download(String path, HttpServletResponse response) {
    try {
        // path是指想要下載的檔案的路徑
        File file = new File(path);
        log.info(file.getPath());
        // 獲取檔名
        String filename = file.getName();
        // 獲取檔案字尾名
        String ext = filename.substring(filename.lastIndexOf(".") + 1).toLowerCase();
        log.info("檔案字尾名：" + ext);

        // 將檔案寫入輸入流
        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();
        // 設定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檔案，用瀏覽器開啟還是以附件的形式下載到本地儲存
        //attachment表示以附件方式下載   inline表示線上開啟   "Content-Disposition: inline; filename=檔名.mp3"
        // filename表示檔案的預設名稱，因為網路傳輸只支援URL編碼的相關支付，因此需要將檔名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"));
        // 告知瀏覽器檔案的大小
        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     指想要下載的檔案的路徑
* @param response
* @功能描述 下載檔案:將輸入流中的資料迴圈寫入到響應輸出流中，而不是一次性讀取到記憶體
*/
@RequestMapping("/downloadLocal")
public void downloadLocal(String path, HttpServletResponse response) throws IOException {
   // 讀到流中
   InputStream inputStream = new FileInputStream(path);// 檔案的存放路徑
   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位元組，並將其儲存在緩衝區位元組陣列中，讀到末尾返回-1
   while ((len = inputStream.read(b)) > 0) {
       outputStream.write(b, 0, len);
   }
   inputStream.close();
}

/**
* @param path       下載後的檔案路徑和名稱
* @param netAddress 檔案所在網路地址
* @功能描述 網路檔案下載到伺服器本地
*/
@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 網路檔案獲取到伺服器後，經伺服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) {
        // 線上開啟方式 檔名應該編碼成UTF-8
        response.setHeader("Content-Disposition", "inline; filename=" + URLEncoder.encode(filename, "UTF-8"));
    } else {
        //純下載方式 檔名應該編碼成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")