string(248) "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%88%86%E4%B8%BA%E5%93%AA%E5%87%A0%E7%A7%8D%E6%83%85%E5%86%B5 => Failed to connect to 101.91.112.32 port 38221: Connection refused"
短路分为哪几种情况
