string(257) "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%E5%AE%9A%E4%B9%89%E6%98%AF%E4%BB%80%E4%B9%88 => Failed to connect to 101.89.120.29 port 38025: Connection refused"
短路和断路定义是什么
