浏览器文件下载读取本地文件

/**
 * 文件下载
 * @param fileName
 * @param filePath
 * @param request
 * @param response
 * @return
 */
@RequestMapping("/download")
public String download( String fileName ,String filePath, HttpServletRequest request, HttpServletResponse response){

   response.setContentType("text/html;charset=utf-8");
   try {
      request.setCharacterEncoding("UTF-8");
   } catch (UnsupportedEncodingException e1) {
      // TODO Auto-generated catch block
      e1.printStackTrace();
   }

   java.io.BufferedInputStream bis = null;
   java.io.BufferedOutputStream bos = null;
   String downLoadPath = filePath;  //注意不同系统的分隔符
   System.out.println(downLoadPath);

   try {
      long fileLength = new File(downLoadPath).length();
      response.reset();
      response.setContentType("application/x-msdownload;");
      String userAgent = request.getHeader("user-agent").toLowerCase();
      //处理是否是ie浏览器
      if (userAgent.contains("msie") || userAgent.contains("like gecko") ){
         response.setHeader("Content-disposition", "attachment; filename=" + new String(URLEncoder.encode(fileName, "UTF-8")));
      }else {
         response.setHeader("Content-disposition", "attachment; filename=" + new String(fileName.getBytes("utf-8"), "iso-8859-1"));
      }
      response.setHeader("Content-Length", String.valueOf(fileLength));

      bis = new BufferedInputStream(new FileInputStream(downLoadPath));
      bos = new BufferedOutputStream(response.getOutputStream());
           byte[] buff = new byte[1024];
      // 将数据写入输出流
      int bytesRead;
      while (-1 != (bytesRead = bis.read(buff, 0, buff.length))) {
         bos.write(buff, 0, bytesRead);
      }
   } catch (Exception e) {
      e.printStackTrace();
   } finally {
      if (bis != null)
         try {
            bis.close();
         } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
         }
      if (bos != null)
         try {
            bos.close();
         } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
         }
   }
   return null;
}