linux 文件夹权限

  Runtime r = Runtime.getRuntime();
        Process p = r.exec("ls -ld " + inputDir);
        int ret = p.waitFor();
        if (ret == 0)
        {
            byte[] buf = new byte[1024];
            InputStream is = p.getInputStream();
            int len = is.read(buf);

            String cmdLine = new String(buf, 0, len);
            int idx = cmdLine.indexOf(' ');
            if (idx != -1 && cmdLine.substring(0, idx).indexOf("rwxrwxrwx") != -1)
            {
                return inputDir;
            }
            throw new Exception(inputDir + "，目录权限必须为777。请使用sudo chmod 777 <dirname>设置！");
        }