根据ip获取地理位置

使用到的是淘宝提供的API

1. 请求接口（GET）：

http://ip.taobao.com/service/getIpInfo.php?ip=[ip地址字串]

2. 响应信息：

（json格式的）国家 、省（自治区或直辖市）、市（县）、运营商

3. 返回数据格式：

{"code":0,"data":{"ip":"210.75.225.254","country":"\u4e2d\u56fd","area":"\u534e\u5317",
"region":"\u5317\u4eac\u5e02","city":"\u5317\u4eac\u5e02","county":"","isp":"\u7535\u4fe1",
"country_id":"86","area_id":"100000","region_id":"110000","city_id":"110000",
"county_id":"-1","isp_id":"100017"}}