string(251) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E6%89%8B%E6%9C%BAapp%E5%BC%80%E5%8F%91%E9%9C%80%E8%A6%81%E5%AD%A6%E4%BB%80%E4%B9%88 => Failed to connect to 101.91.112.32 port 38162: Connection refused"
手机app开发需要学什么
