How to send string data to socket connection via telnet or any other program? - string

Question

I am trying to send and receive string data to socket connection via telnet, but I am not able to type or see anything in the telnet window. I am able to connect to the server via telnet, but not able to send the string data.
Is there any other alternate method to send string data over socket connection.

Answer 1

Telnet, unless it negotiates parameters to the contrary, does "remote echo" meaning that you won't see anything you type unless the server echos it back.
A lot of people use the term "Telnet" when really it is a raw socket connection that does no configuration negotiation upon connect.
If you're sending data from a file or source other than the keyboard (and even often when sending from the keyboard), you're better of using a program like socket or nc (netcat) which don't attempt to do any processing of the data stream and so provide simple 8-bit clean connections.
In the case of both those problems, you can simply redirect stdin from a file or echo a string to them through a pipe.

Answer 2

i have a example of a server that talks to with many telnet client.
You must use the class DataInputStream and DataOutputStream
You must use A Class Implements Runnable for establish multiple sessions
You must use a ServerSocket Class.
Good, this is the code of the main class called SocketServerExample:
import java.net.*;
import java.io.*;
import socketserverexample.ThreadServer;
/**
*
* #author JuanLuisHiciano
*/
public class SocketServerExample {
public static void main(String args[]) throws InterruptedException {
ServerSocket mi_servicio = null;
String linea_recibida;
DataInputStream entrada = null;
DataOutputStream salida = null;
Socket socket_conectado = null;
try {
mi_servicio = new ServerSocket(2017);
}
catch (IOException excepcion) {
System.out.println(excepcion);
}
try {
int n=1;
while(n<2){
socket_conectado = mi_servicio.accept();
System.out.println("Un cliente se a conectado "+socket_conectado.getPort());
entrada= new DataInputStream(socket_conectado.getInputStream());
String nombre = entrada.readUTF();
// Se instancia una clase para atender al cliente y se lanza en
// un hilo aparte.
Runnable nuevoCliente = new ThreadServer(nombre, socket_conectado); //Input and Output data Channels
Thread hilo = new Thread(nuevoCliente);
hilo.start();
}
salida.writeUTF("Fin de la conexion....");
salida.close();
entrada.close();
socket_conectado.close();
}
catch (IOException excepcion) {
System.out.println(excepcion);
}
}
}
ok,This run de Main Server with the UTP port (2017) and delivering sessions to other threads to receive new connections.
Good , below is the code of the class Called ThreadServer :
import java.net.*;
import java.io.*;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
*
* #author JuanLuisHiciano
*/
public class ThreadServer implements Runnable{
DataInputStream entrada;
DataOutputStream salida;
Socket socket_conectado = null;
String linea_recibida;
String cliente;
ThreadServer(String cliente,Socket socket) {
socket_conectado = socket;
this.cliente=cliente;
}
#Override
public void run() {
int n=0;
while(n<3){
try {
salida = new DataOutputStream(socket_conectado.getOutputStream());
entrada = new DataInputStream(socket_conectado.getInputStream());
//System.out.println("Confirmando Conexion al cliente .....");
salida.writeUTF("Conexion Exitosa\n");
salida.writeUTF("Puede compartir un mensaje : ");
//recepcion de mensaje
linea_recibida = entrada.readUTF();
System.out.println(cliente+" dice: "+linea_recibida);
System.out.println(socket_conectado.getPort());
n++;
} catch (IOException ex) {
Logger.getLogger(ThreadServer.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
}
With this code you can talk to each of the clients connecting.
Goodbye Saludos de Republica Dominicana
I hope you serve something this code.