string(240) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=b2b%E6%A8%A1%E5%BC%8F%E7%9A%84%E7%89%B9%E7%82%B9%E6%9C%89%E5%93%AA%E4%BA%9B => Failed to connect to 14.18.46.51 port 38206: Connection refused"
b2b模式的特点有哪些
