string(245) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=usb3.0%E4%BC%A0%E8%BE%93%E9%80%9F%E5%BA%A6%E5%8F%AA%E6%9C%89%E5%87%A0%E7%99%BEk => Failed to connect to 14.18.117.71 port 38164: Connection refused"
usb3.0传输速度只有几百k
