java web上传文件和下载文件代码片段分享

 /**  * Purpose：上传文档  *   * @param req  * @param fileTitle  * @param fileType  * @param fileDesc  * @return  */ @RequestMapping("upload") public ModelAndView upload(HttpServletRequest req, String fileType, String fileDesc, String share) {  UserAllInfo userAll = (UserAllInfo) req.getSession().getAttribute("userAll");  ModelAndView mav = new ModelAndView();  // 获取文件的大小  String fileSize = "";  int length = req.getContentLength();  //转换成KB  double len1 = (double) (Math.round((length / 1024) * 100)) / 100;  //转换成MB  double len2 = (double) (Math.round((len1 / 1024) * 100)) / 100;  if (len2 > 1) {   fileSize = String.valueOf(len2) + "MB";  } else {   fileSize = String.valueOf(len1) + "KB";  }  //将请求转换成处理文件的请求  MultipartRequest mreq = (MultipartRequest) req;  //文件上传专用类  MultipartFile mfile = mreq.getFile("uploadFile");  // 得到上下文路径  String root = req.getSession().getServletContext().getRealPath("/");  File dir = new File(root);  // 获取文件名和文件的mime类型  String str = mfile.getOriginalFilename();  String[] st = str.split("//.");  File savedFile = null;  try {   //在指定目录中创建一个新的空文件，文件名称加前缀"upload_"   savedFile = File.createTempFile("upload_", mfile.getOriginalFilename(), dir);   //将缓冲区的内容复制到新创建的文件中   FileCopyUtils.copy(mfile.getInputStream(), new FileOutputStream(savedFile));  } catch (Exception e) {   e.printStackTrace();  }  String path = savedFile.getPath();  // 将文件的信息封装在对象中  FileInfo file = new FileInfo();  if (userAll != null) {   file.setUploadPersonId(userAll.getUser().getUserId());  } else {   mav.setViewName("login");   return mav;  }  file.setFileName(st[0]);  file.setFilePath(path);  Date date = new Date();  file.setUploadDate(date);  file.setFileSize(fileSize);  file.setFileType(fileType);  file.setFileForm(st[1]);  if ("superman".equals(userAll.getUser().getUserNumber())) {   file.setFileShare("Y");   file.setCheckFlag("Y");  } else {   file.setFileShare(share);   file.setCheckFlag("N");  }  file.setDeleteFlag("N");  file.setDownloadTimes(0);  // 保存文件的信息  boolean bool = fileSer.saveFile(file);  String userNumber = userAll.getUser().getUserNumber();  //设置跳转界面  mav.setViewName("jsp/person/upload");  logSer.saveLog("用户/"" + userNumber + "/"上传文件/"" + file.getFileName() + "/"");  mav.getModel().put("bool", bool);  return mav; } /**  * Purpose：下载文档  *   * @param fileId 文件id  * @return  */ @RequestMapping("download") public void download(Integer fileId, HttpServletResponse resp) {  FileInfo file = new FileInfo();  //通过文件id获取文件的基本信息  file = fileSer.getFileById(fileId);  // 根据文件后缀名设置文件的mime类型  String mime = "application/";  switch (file.getFileForm()) {  case "doc":   mime = mime + "msword";   break;  case "docx":   mime = mime + "msword";   break;  case "pdf":   mime = mime + "pdf";   break;  case "xls":   mime = mime + "vnd.ms-excel";  case "ppt":   mime = mime + "vnd.ms-powerpoint";   break;  case "txt":   mime = "text/plain";   break;  default:   break;  }  resp.setContentType(mime);  String fileName = file.getFileName();  String name = "";  try {   // 将文件名使用utf-8编码格式编码，使其中的中文字符可以正常显示   name = URLEncoder.encode(fileName, "utf-8");  } catch (UnsupportedEncodingException e1) {   e1.printStackTrace();  }  // 弹框选择保存路径  resp.setHeader("content-disposition", "attachment;filename=" + name + "." + file.getFileForm()    + ";filename*=utf-8''" + name + "." + file.getFileForm());  String filePath = file.getFilePath();  InputStream is = null;  OutputStream os = null;  try {   is = new BufferedInputStream(new FileInputStream(filePath));   os = new BufferedOutputStream(resp.getOutputStream());   byte[] buff = new byte[1024];   @SuppressWarnings("unused")   int count;   while ((count = is.read(buff)) != -1) {    os.write(buff);   }   //修改下载次数   fileSer.update(fileId);  } catch (Exception e) {   e.printStackTrace();  } finally {   //最后，要记得关闭输入流和输出流   if (is != null) {    try {     is.close();    } catch (IOException e) {     e.printStackTrace();    }   }   if (os != null) {    try {     os.close();    } catch (IOException e) {     e.printStackTrace();    }   }  } }