Tbta va dtkafedrasi tarmoqni dasturlash asoslari

NVTPriter sinf kodi

class NVTPrinter extends Thread {

NVTInputStream inStream;

public NVTPrinter(NVTInputStream in){

//super();

inStream=in;

}

public void run(){

boolean finished=false;

try{

do{

int i=inStream.read();

if(i==-1){

finished=true;

}

else{

System.out.print((char)i);

System.out.flush();

yield();

}

//System.out.println("\n");

}while(!finished);

System.out.println("The Connection is aborted....");

System.exit(1);

}catch(IOException e){

System.out.println("Network Virtual Terminal Error");

}}

NVTOutputStream klassi

class NVTOutputStream extends FilterOutputStream{

int IAC=255;

byte CR=13;

byte LF=10;

public NVTOutputStream(OutputStream output){

super(output);

}

public void write(int i) throws IOException{

super.write(i);

}

public void println(String s){

try{

byte [] bytes=s.getBytes();

for(int i=0;i

super.write(bytes[i]);

}

super.write(CR);

super.write(LF);

super.flush();

}catch(IOException e){

System.out.println(" Input output Error");

} } }

NVTInputStream klassi

class NVTInputStream extends FilterInputStream{

byte IAC=(byte)0xFF;

byte DO=(byte)0xFD;

byte WILL =(byte)0xFB;

byte CR=13;

byte LF=10;

int wont=252;

int dont=254;

int bufferSize=1024;

OutputStream out;

byte [] linebuf=new byte[bufferSize];

int numBytes=0;

public NVTInputStream(InputStream inStream,OutputStream outStream){

super(inStream);

out=outStream;

}

public int read () throws IOException{

boolean recIAC;

int i;

do{

recIAC=false;

i=in.read();

if(i==-1) {

return i;

}

else if(IAC==i){

recIAC=true;

int cmd=in.read();

if(cmd==-1){

return cmd;

}

else{

byte b2=(byte)cmd;

if(b2==IAC){

return 255;

}

if(b2==WILL){

int opt=in.read();

if(opt==-1){

return opt;

}

out.write(255);

out.write(dont);

out.write(opt);

out.flush();

}

if(b2==DO){

int opt=in.read();

if(opt==-1){

return opt;

}

out.write(255);

out.write(wont);

out.write(opt);

out.flush();

} } }

}while(recIAC); return i; }

public String readLine() throws IOException {

numBytes=0;

boolean finished=false;

do{

int i=read();

if(i==-1)

return null;

else{

byte b=(byte)i;

if(b==LF){

if(numBytes>0){

if(linebuf[numBytes-1]==13){

return new String(linebuf,0,numBytes-1);

} } }

linebuf[numBytes]=b;

++numBytes;

}

}while(!finished);

return null; } }

Port klassi

class port extends Thread{

Socket con;

OutputStream out;

NVTInputStream in;

NVTPrinter printer;

public port(String [] args){

System.out.println("length"+args.length);

if(args.length!=2){

System.out.println("Use: Java Telnet host port");

System.exit(2);

}

String destination=args[0];

int port =0;

port=Integer.parseInt(args[1]);

System.out.println("Connecting to "+destination +" on " +port);

try{

con=new Socket(destination,port);

}catch(UnknownHostException e){

System.out.println("Unknown Destination..Try again...");

System.exit(3);

}

catch(IOException e){

System.out.println("Error While Creating the Socket");

System.exit(3);

}

try{

out=con.getOutputStream();

in=new NVTInputStream(con.getInputStream(),out);

}catch(IOException e){

System.out.println("Input Output Error...");

System.exit(3);

}

System.out.println("Connection Established..");

}

public void ProcessInput(){

try{

String line;

boolean finished=false;

BufferedReader read=new BufferedReader(new InputStreamReader(System.in));

do{

line=read.readLine();

if(line==null){

finished=true;

}else{

try{

for(int i=0;iout.write(line.charAt(i));

out.write('\n');

}

}catch(IOException e){

System.out.println("Input Output Error...");

System.exit(3);

}

}

}while(!finished);

} catch(IOException e){

System.out.println("Input Output Error...");

System.exit(3);

}

}

public void shutdown(){

try{

con.close();

}catch(IOException e){

System.out.println("Error Closing the Socket");

System.exit(3);

}

}

public void run(){

printer =new NVTPrinter(in);

printer.start();

yield();

this.ProcessInput();

shutdown();

}

}

Telnet sinf namunasi

//This is a sample Telnet app coded using java

import java.net.*;

import java.rmi.UnknownHostException;

import java.io.*;

Public class Telnet {

public static void main(String [] str){

for(int i=0;i

System.out.println("<<>>"+str[i]);

}

port p=new port(str);

p.start();

}

}