java - 使用通配符 IP 地址获取域名

Question

我正在尝试编写一个类，该类将从/etc/hosts 文件中的 IP 地址返回域名。例如，我知道 Google 拥有的 IP 地址 block 是 74.125.0.0 - 74.125.255.255 并且在我的主机文件中；

74.125.24.155   Google
74.125.24.101   Google
74.125.24.102   Google
74.125.24.132   Google
74.125.24.113   Google
74.125.24.84   Google

我编写了一段简单的代码，它将查找主机文件并搜索相应 IP 地址的名称。这是代码；

String destination = "74.125.24.84";
InetAddress address = InetAddress.getByName(destination);
String resolvedHost = address.getHostName();
System.out.println("Translated " + destination + " to host name " + resolvedHost);

这将返回以下Translated 74.125.24.84 to host name Google。然后我尝试了；

String destination = "74.125.24.*";
InetAddress address = InetAddress.getByName(destination);
String resolvedHost = address.getHostName();
System.out.println("Translated " + destination + " to host name " + resolvedHost);

但响应中出现以下错误；

java.net.UnknownHostException: 74.125.24.*
at java.net.Inet6AddressImpl.lookupAllHostAddr(Native Method)
at java.net.InetAddress$1.lookupAllHostAddr(Unknown Source)
at java.net.InetAddress.getAddressesFromNameService(Unknown Source)
at java.net.InetAddress.getAllByName0(Unknown Source)
at java.net.InetAddress.getAllByName(Unknown Source)
at java.net.InetAddress.getAllByName(Unknown Source)
at java.net.InetAddress.getByName(Unknown Source)
at IPToDomainName.main(IPToDomainName.java:12)

是否可以使用通配符来表示 Google 的 IP 地址？

Answer 1

你能迭代它吗？

for (int i=0;i<=255;i++) {
    String destination = "74.125.24." + i;
    InetAddress address = InetAddress.getByName(destination);

    if (address == null) // Or any exception.
         continue;

    String resolvedHost = address.getHostName();

    System.out.println("Translated " + destination + " to host name " + resolvedHost);
}