using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace CSharpStudy
{
class Program
{
static void Main(string[] args)
{
string url = "http://www.xinhuanet.com/2018-08/02/c_1123215278.htm";
//string url = "http://news.ifeng.com/a/20180803/59600750_0.shtml";
Uri uri = new Uri(url);
string topDomain = GetBaseDomain(uri.Host);
Console.WriteLine("当前域名:" + uri.Host);
Console.WriteLine("一级域名:" + topDomain);
Console.ReadKey();
}
private static string GetBaseDomain(string host)
{
HashSet<string> HashSet = new HashSet<string>(".com|.co|.info|.net|.org|.me|.mobi|.us|.biz|.xxx|.ca|.co.jp|.com.cn|.net.cn|.org.cn|.mx|.tv|.ws|.ag|.com.ag|.net.ag|.org.ag|.am|.asia|.at|.be|.com.br|.net.br|.bz|.com.bz|.net.bz|.cc|.com.co|.net.co|.nom.co|.de|.es|.com.es|.nom.es|.org.es|.eu|.fm|.fr|.gs|.in|.co.in|.firm.in|.gen.in|.ind.in|.net.in|.org.in|.it|.jobs|.jp|.ms|.com.mx|.nl|.nu|.co.nz|.net.nz|.org.nz|.se|.tc|.tk|.tw|.com.tw|.idv.tw|.org.tw|.hk|.co.uk|.me.uk|.org.uk|.vg".Split('|'));
string[] hs = host.Split(".".ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
if (hs.Length > 2)
{
//传入的host地址至少有三段
int p2 = host.LastIndexOf('.'); //最后一次“.”出现的位置
int p1 = host.Substring(0, p2).LastIndexOf('.');//倒数第二个“.”出现的位置
string s1 = host.Substring(p1);
if (!HashSet.Contains(s1))
return s1.TrimStart('.');
//域名后缀为两段(有用“.”分隔)
if (hs.Length > 3)
return host.Substring(host.Substring(0, p1).LastIndexOf('.'));
else
return host.TrimStart('.');
}
else if (hs.Length == 2)
{
return host.TrimStart('.');
}
else
{
return string.Empty;
}
}
}
}