string(234) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=b2b%E6%9C%89%E5%93%AA%E5%87%A0%E7%A7%8D%E6%A8%A1%E5%BC%8F%E7%9A%84 => Failed to connect to 101.89.143.195 port 38109: Connection refused"
b2b有哪几种模式的
