spring_mvc_down_file

最新推荐文章于 2025-11-27 11:45:47 发布

原创最新推荐文章于 2025-11-27 11:45:47 发布 · 365 阅读

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本文介绍了两种不同的文件下载方法实现方式，一种使用了传统的输入输出流处理，另一种则利用了Spring框架提供的ResponseEntity来完成文件的下载操作。文章通过具体代码展示了如何从服务器获取指定路径下的文件，并将其发送给客户端。

@Deprecated
@RequestMapping("/download2/{suffix}/{filename}")
public String download2(HttpServletRequest request, HttpServletResponse response, @PathVariable("suffix") String suffix, @PathVariable("filename") String filename) {
   String filenameWithSuffix = filename + "." +suffix;
   try {
      String path=request.getSession().getServletContext().getRealPath("download");
File file = new File(path + File.separator + filenameWithSuffix);

// 以流的形式下载文件。
InputStream fis = new BufferedInputStream(new FileInputStream(file));
      byte[] buffer = new byte[fis.available()];
fis.read(buffer);
fis.close();

response.reset(); // 清空response
      // 设置response的Header
      //response.addHeader("Content-Disposition", "attachment;filename=" + new String(filenameWithSuffix.getBytes(),"utf-8"));
response.addHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(filenameWithSuffix, "UTF-8"));
response.addHeader("Content-Length", "" + file.length());
OutputStream toClient = new BufferedOutputStream(response.getOutputStream());
response.setContentType("application/octet-stream");
toClient.write(buffer);
toClient.flush();
toClient.close();

} catch (FileNotFoundException e) {
      e.printStackTrace();
} catch (IOException e) {
      e.printStackTrace();
}
   //  返回值要注意，要不然就出现下面这句错误！
//java+getOutputStream() has already been called for this response
return null;
}

@RequestMapping("/download/{suffix}/{filename}")
public ResponseEntity<byte[]> download(HttpServletRequest request, @PathVariable("suffix") String suffix, @PathVariable("filename") String filename) {
   String filenameWithSuffix = filename + "." +suffix;
HttpHeaders headers = new HttpHeaders();
   try {
      headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
headers.setContentDispositionFormData("attachment", URLEncoder.encode(filenameWithSuffix, "UTF-8"));

String path=request.getSession().getServletContext().getRealPath("download");
      return new ResponseEntity<byte[]>(FileUtils.readFileToByteArray(new File(path + File.separator + filenameWithSuffix)), headers, HttpStatus.CREATED);
} catch (FileNotFoundException e) {
      e.printStackTrace();
} catch (IOException e) {
      e.printStackTrace();
}
   return null;
}

第一个方法太low ^_^