string(265) "get document error：https://zhidao.baidu.com/search?lm=0&rn=10&pn=0&fr=search&dyTabStr=null&word=%E8%AF%B7%E7%AE%80%E8%BF%B0%E5%9F%BA%E5%B0%BC%E7%B3%BB%E6%95%B0%E7%9A%84%E4%BC%98%E7%BC%BA%E7%82%B9 => Failed to connect to 14.18.117.71 port 38069: Connection refused"
请简述基尼系数的优缺点
