根据当前IP获取当时所在信息

　　现在很多系统，都要在登录时候，确定当前用户所在的位置。这里记录一个C#使用Http的方式获取当前IP所在的位置信息。主要使用的api是新浪的接口。

public partial class sina : System.Web.UI.Page
{
    protected string ip = "171.216.18.89";
    protected void Page_Load(object sender, EventArgs e)
    {
        //if (IPOperation.GetIP() != "127.0.0.1")
        //{
        //    ip = IPOperation.GetIP();
        //}
        this.ClientScript.RegisterStartupScript(this.GetType(), "message", "<script language='javascript' defer>alert('" + GetCityByIP(ip).ToString() + "');</script>");

    }
    private string GetCityByIP(string ip)
    {
        string cityName = "成都";
        if (!string.IsNullOrEmpty(ip))
        {
            string url = "http://int.dpool.sina.com.cn/iplookup/iplookup.php?format=js&ip=" + ip;
            HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;
            request.Method = "POST";
            request.ContentType = "application/json;charset=utf-8";
            Stream stream = request.GetResponse().GetResponseStream();
            StreamReader sr = new StreamReader(stream, Encoding.UTF8);
            string str = sr.ReadToEnd().Split('=')[1].ToString().TrimEnd(';');


            IPArea list = new JavaScriptSerializer().Deserialize<IPArea>(str);
            cityName = list.city;
        }
        return cityName;
    }
}
class IPArea
{
    public int ret { get; set; }
    public string start { get; set; }
    public string end { get; set; }
    public string country { get; set; }
    public string province { get; set; }
    public string city { get; set; }
    public string district { get; set; }
    public string isp { get; set; }
    public string type { get; set; }
    public string desc { get; set; }
}

　　主要先创建一个HttpWebRequest，定义请求方式及返回数据的结构和编码。这里使用JavaScriptSerializer将返回的json对象反序列化为对象。关于对象的信息就不记载了。