import java.net.InetAddress;
import java.net.UnknownHostException;
/**
獲取IP地址和域名
*/
public class GetIPAddress{
    //通過InetAddress靜態方法獲取本機網路地址資訊,在通過InetAddress例項方法獲取本機網路IP資訊
    //host包括hostname/hostaddress
    public String getLocalIP() throws UnknownHostException{
        System.out.println("InetAddress-localhost: "+InetAddress.getLocalHost().toString());
        System.out.println(
 
"getLocalIP: "+InetAddress.getLocalHost().getHostAddress());
        return InetAddress.getLocalHost().getHostAddress();
        }
    //通過InetAddress例項方法獲取本機的域名或者主機名
    public String getHostName() throws UnknownHostException{
        System.out.println("getHostName: "+InetAddress.getLocalHost().getHostName());
        
 
return InetAddress.getLocalHost().getHostName();
        }
    //通過InetAddress靜態方法通過域名獲取網路資訊(InetAddress)
    //getHostAddress()和getHostAddress()是相對的，如果沒有指定引數則是相對於本機，如果指定引數就是相對於指定的引數
    public String getIPByName(String str) throws UnknownHostException{
        System.out.println("域名為"+str+"的IP： "+InetAddress.getByName(str).getHostAddress());
        
 
return InetAddress.getByName(str).getHostAddress();
        }
    //通過InetAddress靜態方法通過域名獲取多IP本機網路資訊(InetAddress)
    public String[] getAllIPByName(String str) throws UnknownHostException{
        System.out.println("域名為"+str+"的所有IP： ");
        int numIP = InetAddress.getAllByName(str).length;
        InetAddress[] inetAddress = InetAddress.getAllByName(str);
        String[] IPs = new String[numIP];
        for(int i=0;i<numIP;i++){
            String temp = inetAddress[i].getHostAddress();
            IPs[i] = temp;
            System.out.println("IP["+i+"]： "+temp);
            }
        return IPs;
        }
    public static void main(String[] args) throws UnknownHostException{
        GetIPAddress getIP = new GetIPAddress();
        getIP.getLocalIP();
        System.out.println("======================================================");
        getIP.getHostName();
        System.out.println("======================================================");
        getIP.getIPByName("www.google.cn");
        System.out.println("======================================================");
        getIP.getAllIPByName("www.google.cn");
        }
    }

編譯執行結果：
G:\maul keyboard\network programming>javac GetIPAddress.java

G:\maul keyboard\network programming>java GetIPAddress
InetAddress-localhost: MS-20160816QAVW/10.0.216.208
getLocalIP: 10.0.216.208
======================================================
getHostName: MS-20160816QAVW
======================================================
域名為www.google.cn的IP： 203.208.40.127
======================================================
域名為www.google.cn的所有IP：
IP[0]： 203.208.40.127
IP[1]： 203.208.40.120
IP[2]： 203.208.40.111
IP[3]： 203.208.40.119

G:\maul keyboard\network programming>