java查询dns解析是否生效

import java.net.InetAddress;
import java.net.UnknownHostException;

public class DNSQuery {
    public static void main(String[] args) {
        try {
            String host = "www.example.com"; // 要查询的主机名
            InetAddress inetAddress = InetAddress.getByName(host);
            
            System.out.println("主机名: " + inetAddress.getHostName());
            System.out.println("IP地址: " + inetAddress.getHostAddress());
        } catch (UnknownHostException e) {
            System.out.println("无法解析主机名");
            e.printStackTrace();
        }
    }
}

import java.net.InetAddress;
import java.io.IOException;

public class DNSQuery {
    public static void main(String[] args) {
        try {
            String host = "www.example.com"; // 要查询的主机名
            InetAddress inetAddress = InetAddress.getByName(host);
            
            boolean isReachable = inetAddress.isReachable(5000); // 超时时间为5秒
            
            if (isReachable) {
                System.out.println("主机可达");
            } else {
                System.out.println("主机不可达");
            }
        } catch (IOException e) {
            System.out.println("无法解析主机名或网络错误");
            e.printStackTrace();
        }
    }
}