code: public static File getParent(File file, int level) {
  		if (level < 1 || null == file) {
  			return file;
  		}
  
  		File parentFile;
  		try {
  			parentFile = file.getCanonicalFile().getParentFile();
  		} catch (IOException e) {
  			throw new IORuntimeException(e);
  		}
  		if (1 == level) {
  			return parentFile;
  		}
  		return getParent(parentFile, level - 1);
  	}
docs: 获取指定层级的父路径
  
  <pre>
  getParent(file("d:/aaa/bbb/cc/ddd", 0)) -> "d:/aaa/bbb/cc/ddd"
  getParent(file("d:/aaa/bbb/cc/ddd", 2)) -> "d:/aaa/bbb"
  getParent(file("d:/aaa/bbb/cc/ddd", 4)) -> "d:/"
  getParent(file("d:/aaa/bbb/cc/ddd", 5)) -> null
  </pre>
  
  @param file 目录或文件
  @param level 层级
  @return 路径File，如果不存在返回null
  @since 4.1.2