string(256) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E6%B5%8B%E6%B0%B4%E6%B5%81%E9%87%8F%E7%9A%84%E4%BB%AA%E5%99%A8%E7%94%A8%E4%BB%80%E4%B9%88 => Failed to connect to 14.116.215.7 port 38225: Connection refused"
测水流量的仪器用什么
