javaweb简单的实现文件下载

public HttpServletResponse download(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

      //解决乱码问题
      String path = new String(request.getParameter("filepath").getBytes("ISO8859-1"),"utf-8");
      String filename = "";
      if(path != null){  //分割字符串，获取文件名称
         String file[] = path.split("\\");
         filename = file[file.length-1];
      }
      //注意这里的路径必须是文件的全路径，如果是文件夹的话就会报错拒绝访问
//    String path = "D:\idea_workspase\jeesite\target\jeesite\my\周工作总结-软件部(5).xlsx";
      try {
         // path是指欲下载的文件的路径。
         File file = new File(path);
         // 取得文件名。
//            String filename = file.getName();
//       String filename = "周工作总结-软件部(5).xlsx";
         // 取得文件的后缀名。
         String ext = filename.substring(filename.lastIndexOf(".") + 1).toUpperCase();

         // 以流的形式下载文件。
         InputStream fis = new BufferedInputStream(new FileInputStream(path));
         byte[] buffer = new byte[fis.available()];
         fis.read(buffer);
         fis.close();
         // 清空response
         response.reset();
         // 设置response的Header
//       response.addHeader("Content-Disposition", "attachment;filename=" + new String(filename.getBytes()));
         response.setHeader( "Content-Disposition", "attachment;filename=" + new String( filename.getBytes("GBK"), "ISO8859-1" ) );
         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 (IOException ex) {
         ex.printStackTrace();
      }
      return response;
   }