修正方法: Java ネットワーク エラー: ホスト名を解決できません

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

public class DNSExample {
    public static void main(String[] args) {
        try {
            // 获取系统默认的DNS设置
            InetAddress dns = InetAddress.getByName("www.example.com");
            System.out.println("System DNS: " + dns.getHostAddress());

            // 修改DNS设置
            InetAddress alternativeDNS = InetAddress.getByName("8.8.8.8");
            System.setProperty("sun.net.spi.nameservice.provider.1", "dns,sun");
            System.setProperty("sun.net.spi.nameservice.nameservers", alternativeDNS.getHostAddress());
            
            // 再次获取DNS设置并打印
            dns = InetAddress.getByName("www.example.com");
            System.out.println("Modified DNS: " + dns.getHostAddress());
        } catch (UnknownHostException e) {
            e.printStackTrace();
        }
    }
}

import java.net.InetSocketAddress;
import java.net.Proxy;
import java.net.URL;
import java.net.URLConnection;

public class ProxyExample {
    public static void main(String[] args) {
        try {
            // 配置代理服务器
            Proxy proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress("proxy.example.com", 8080));
            URL url = new URL("http://www.example.com");
            
            // 打开连接
            URLConnection conn = url.openConnection(proxy);
            conn.connect();
            System.out.println("Connected!");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}