code: public static Prop useFirstFound(String... fileNames) {
  		for (String fn : fileNames) {
  			try {
  				return use(fn, Const.DEFAULT_ENCODING);
  			} catch (Exception e) {
  				continue ;
  			}
  		}
  		
  		throw new IllegalArgumentException("没有配置文件可被使用");
  	}
docs: Use the first found properties file