如何在Java中检查域是否存在？
假设我的电子邮件地址是 xyz@yahoo.com ，我想检查 yahoo.com 是否是是否有效域。
Suppose my email address is xyz@yahoo.com and I want to check if yahoo.com is a valid domain or not.
有谁能告诉我我可以使用哪种Java API？
Can anyone tell me which Java API I can use for this?
InetAddress 有 getByName（） 方法确定主机的IP地址，鉴于主持人的名字。
InetAddress has getByName() method to determine the IP address of a host, given the host's name.
如果找不到主机的IP地址（如果给定的主机名无效）， 将抛出UnknownHostException 。
If no IP address for the host could be found ( in case the given host name is not valid) , UnknownHostException will be thrown.
因此，您只需在调用 InetAddress.getByName（）时尝试捕获。如果捕获到 UnknownHostException UnknownHostException ，则表示您的输入主机名无效。
So , you just try to catch an UnknownHostException when calling InetAddress.getByName() . If UnknownHostException is caught , that means your input host name is invalid.