方式一：

1 import java.net.MalformedURLException; 2 import java.net.URL; 3 import java.util.Arrays; 4 import java.util.HashSet; 5 import java.util.Set; 6 import java.util.regex.Pattern; 7  8 public class URLUtil { 9 10     private final static Set
     
       PublicSuffixSet = new HashSet
      
       (11             Arrays.asList(new String(12                     "com|org|net|gov|edu|co|tv|mobi|info|asia|xxx|onion|cn|com.cn|edu.cn|gov.cn|net.cn|org.cn|jp|kr|tw|com.hk|hk|com.hk|org.hk|se|com.se|org.se")13                     .split("\\|")));14 15     private static Pattern IP_PATTERN = Pattern.compile("(\\d{1,3}\\.){3}(\\d{1,3})");16 17     /**18      * 获取url的顶级域名19      * @param url20      * @return21      */22     public static String getDomainName(URL url) {23         String host = url.getHost();24         if (host.endsWith(".")){25             host = host.substring(0, host.length() - 1);26         }27         if (IP_PATTERN.matcher(host).matches()){28             return host;29         }30 31         int index = 0;32         String candidate = host;33         for (; index >= 0;) {34             index = candidate.indexOf('.');35             String subCandidate = candidate.substring(index + 1);36             if (PublicSuffixSet.contains(subCandidate)) {37                 return candidate;38             }39             candidate = subCandidate;40         }41         return candidate;42     }43 44     /**45      * 获取url的顶级域名46      * @param url47      * @return48      * @throws MalformedURLException49      */50     public static String getDomainName(String url) throws MalformedURLException {51         return getDomainName(new URL(url));52     }53 54     /**55      * 判断两个url顶级域名是否相等56      * @param url157      * @param url258      * @return59      */60     public static boolean isSameDomainName(URL url1, URL url2) {61         return getDomainName(url1).equalsIgnoreCase(getDomainName(url2));62     }63 64     /**65      * 判断两个url顶级域名是否相等66      * @param url167      * @param url268      * @return69      * @throws MalformedURLException70      */71     public static boolean isSameDomainName(String url1, String url2)72             throws MalformedURLException {73         return isSameDomainName(new URL(url1), new URL(url2));74     }75     76     public static void main(String[] args) throws Exception {77         String urlStr = "http://news.hexun.com/2017-09-23/190978248.html";78         getDomainName(urlStr);79         getDomainName(new URL(urlStr));80     }81 82 }
      
     

方式二：

1 import java.net.MalformedURLException; 2 import java.net.URL; 3 import java.util.regex.Matcher; 4 import java.util.regex.Pattern; 5  6 public class DomainUtils { 7     /** 8      * 获取url的顶级域名 9      * @param10      * @return11      */12     public static String getTopDomain(String url){13         try{14             //获取值转换为小写15             String host = new URL(url).getHost().toLowerCase();//news.hexun.com16             Pattern pattern = Pattern.compile("[^\\.]+(\\.com\\.cn|\\.net\\.cn|\\.org\\.cn|\\.gov\\.cn|\\.com|\\.net|\\.cn|\\.org|\\.cc|\\.me|\\.tel|\\.mobi|\\.asia|\\.biz|\\.info|\\.name|\\.tv|\\.hk|\\.公司|\\.中国|\\.网络)");17             Matcher matcher = pattern.matcher(host);18             while(matcher.find()){19                 return matcher.group();20             }21         }catch(MalformedURLException e){22             e.printStackTrace();23         }24         return null;25     }26     public static void main(String[] args) {27         System.out.println(getTopDomain("http://news.hexun.com/2017-09-23/190978248.html"));//hexun.com28 29     }30 }