string(236) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=2021%E6%B6%88%E9%98%B2%E5%B7%A5%E7%A8%8B%E5%B8%88%E6%95%99%E6%9D%90pdf => Failed to connect to 14.18.117.71 port 38133: Connection refused"
2021消防工程师教材pdf
