SpringMvc文件下载

/**
  * 文件下载
  * @Description: 
  * @param fileName
  * @param request
  * @param response
  * @return
  */
  @RequestMapping("/download")
  public String downloadFile(@RequestParam("fileName") String fileName,
          HttpServletRequest request, HttpServletResponse response) {
      if (fileName != null) {
          String realPath = request.getServletContext().getRealPath(
                    "WEB-INF/File/");
          File file = new File(realPath, fileName);
          if (file.exists()) {
              response.setContentType("application/force-download");// 设置强制下载不打开
              response.addHeader("Content-Disposition",
                        "attachment;fileName=" + fileName);// 设置文件名
              byte[] buffer = new byte[1024];
              FileInputStream fis = null;
              BufferedInputStream bis = null;
              try {
                  fis = new FileInputStream(file);
                  bis = new BufferedInputStream(fis);
                  OutputStream os = response.getOutputStream();
                  int i = bis.read(buffer);
                  while (i != -1) {
                      os.write(buffer, 0, i);
                      i = bis.read(buffer);
                  }
              } catch (Exception e) {
                  // TODO: handle exception
                  e.printStackTrace();
              } finally {
                  if (bis != null) {
                      try {
                          bis.close();
                      } catch (IOException e) {
                          // TODO Auto-generated catch block
                          e.printStackTrace();
                      }
                  }
                  if (fis != null) {
                      try {
                          fis.close();
                      } catch (IOException e) {
                          // TODO Auto-generated catch block
                          e.printStackTrace();
                      }
                  }
              }
          }
      }
      return null;
  }