Java api public-suffix-list 返回空域

Question

我使用 java API 根据给定的 URL 提取第二个域名。

https://github.com/whois-server-list/public-suffix-list

它基于 Mozilla 的公共(public)后缀列表。

给出的代码如下:

PublicSuffixListFactory factory = new PublicSuffixListFactory();
    PublicSuffixList suffixList = factory.build();
    String[] domainArray = new String[10];
    domainArray[0] = "swcdn.apple.com";
    domainArray[1] = "production-pdt.siriusxm.com";
    domainArray[2] = "audio2.spotify.com";
    domainArray[3] = "a1935.phobos.apple.com";
    domainArray[4] = "r13---sn-ab5l6n7r.c.pack.google.com";
    domainArray[5] = "a132.phobos.apple.com";
    domainArray[6] = "a1736.phobos.apple.com";
    domainArray[7] = "r17---sn-vgqs7n7l.c.android.clients.google.com";
    domainArray[8] = "s4.amazonaws.com";
    domainArray[9] = "s3.amazonaws.com";

    for(String string : domainArray){
        String domain = suffixList.getRegistrableDomain(string);
        System.out.println(domain);
    }

我得到以下输出:

apple.com
siriusxm.com
spotify.com
apple.com
google.com
apple.com
apple.com
google.com
amazonaws.com
null

它适用于大多数域，但对于 s3.amazonaws.com，它返回 null。然而，对于类似的:s4.amazonaws.com，它给出了正确的结果。有什么问题吗？

Answer 1

s3.amazonaws.com 包含在 public suffix list 中因此被视为不可注册。 PublicSuffixList.getRegistrableDomain()在这种情况下返回 null:

Returns: the registrable domain, null if the domain is not registrable at all