code: public static File openOrCreate(String path,String fileName) throws IOException {
          Path filePath = Paths.get(path, fileName);
          File file = filePath.toFile();
          if (file.exists()) {
              if (file.isFile()) {
                  return file;
              }
              throw new FileNotFoundException(path+" is discroty");
          }else {
              mkirDirs(filePath.getParent());
              file.createNewFile();
              return file;
          }
      }
docs: 打开或者创建
  如果存在就打开，如果不存在就创建
  @param path
  @param fileName
  @return
  @throws IOException