file后台命名参考

              String suffix ="."+ file.getOriginalFilename().substring(file.getOriginalFilename().lastIndexOf(".")+1);
              String filenametime =String.valueOf(System.currentTimeMillis());
              String flieName = filenametime+  suffix
                        /*System.currentTimeMillis()+ file.getOriginalFilename()*/;
              File tempFile = createFile(disk, flieName);
              file.transferTo(tempFile);

suffix为源文件后缀

filenametime为系统当前时间

flieName为具体的存储名