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%8F%AF%E5%88%86%E4%B8%BA%E5%93%AA%E4%B8%A4%E7%B1%BB => Failed to connect to 61.171.74.35 port 38041: Connection refused"
短路可分为哪两类
