string(235) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=cpi%E5%92%8Cppi%E7%9A%84%E8%81%94%E7%B3%BB%E5%92%8C%E5%8C%BA%E5%88%AB => Failed to connect to 61.171.74.35 port 38041: Connection refused"
cpi和ppi的联系和区别
