string(238) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E7%9F%AD%E8%B7%AF%E5%92%8C%E6%96%AD%E8%B7%AF%E7%9A%84%E7%89%B9%E7%82%B9 => Failed to connect to 14.116.215.7 port 38225: Connection refused"
短路和断路的特点
