output: #fixed code
                                  @RequestMapping("/file/downloadFile")
      @ResponseBody
      public void downloadFile(String path, String name, HttpServletRequest request, HttpServletResponse response) {
          response.setHeader("Content-Disposition", "attachment;filename=" + name);
          response.setContentType("application/octet-stream");
          String peersUrl = getPeers().getServerAddress();
          if(StrUtil.isNotBlank(getPeersGroupName())){
              peersUrl += "/"+getPeersGroupName();
          }else {
              peersUrl += "/group1";
          }
          BufferedInputStream in = null;
          try {
              URL url = new URL(peersUrl+path+"/"+name);
              in = new BufferedInputStream(url.openStream());
              response.reset();
              response.setContentType("application/octet-stream");
              response.setHeader("Content-Disposition","attachment;filename=" + URLEncoder.encode(name, "UTF-8"));
              // 将网络输入流转换为输出流
              int i;
              while ((i = in.read()) != -1) {
                  response.getOutputStream().write(i);
              }
              response.getOutputStream().close();
          } catch (IOException e) {
              e.printStackTrace();
          }finally {
              try {
                 if (in != null){
                     in.close();
                 }
              } catch (IOException e) {
                  e.printStackTrace();
              }
          }
      }
input: #vulnerable code 
                                  @RequestMapping("/file/downloadFile")
      @ResponseBody
      public void downloadFile(String path, String name, HttpServletRequest request, HttpServletResponse response) {
          response.setHeader("Content-Disposition", "attachment;filename=" + name);
          response.setContentType("application/octet-stream");
          String peersUrl = getPeers().getServerAddress();
          if(StrUtil.isNotBlank(getPeersGroupName())){
              peersUrl += "/"+getPeersGroupName();
          }else {
              peersUrl += "/group1";
          }
          BufferedInputStream in = null;
          try {
              URL url = new URL(peersUrl+path+"/"+name);
              in = new BufferedInputStream(url.openStream());
              response.reset();
              response.setContentType("application/octet-stream");
              String os = System.getProperty("os.name");
              if(os.toLowerCase().indexOf("windows") != -1){
                  name = new String(name.getBytes("GBK"), "ISO-8859-1");
              }else{
                  //判断浏览器
                  String userAgent = request.getHeader("User-Agent").toLowerCase();
                  if(userAgent.indexOf("msie") > 0){
                      name = URLEncoder.encode(name, "ISO-8859-1");
                  }
              }
              response.setHeader("Content-Disposition","attachment;filename=" + name);
              // 将网络输入流转换为输出流
              int i;
              while ((i = in.read()) != -1) {
                  response.getOutputStream().write(i);
              }
              response.getOutputStream().close();
          } catch (IOException e) {
              e.printStackTrace();
          }finally {
              try {
                 if (in != null){
                     in.close();
                 }
              } catch (IOException e) {
                  e.printStackTrace();
              }
          }
      } 
                              #location 19 
                              #vulnerability type NULL_DEREFERENCE