Java网络编程TCP聊天全双工

Question

I'm implementing a simple tcp chat between a server and a client. I'm using multi-threading so as the server and the client can send and receive data at the same time (full duplex). The program works but if the server has a console for both typing the sending message and also displaying receiving message (same case for client), I cannot edit my typed message that should be sent to server or client when a message has been received from the other side. For eg:

run(server console):

input msg to send client:

you:

client: hi server

client: bye server.

For this example, i've typed a message to send to client while the client has already said hi server bye server. Before receiving from client, i see what i've typed but after receiving, I can't see the msg nor edit it.

I can only use console because im not good with GUI and i want the same console for both sending and receiving data.

The codes for the program are shown below.

import java.net.*;
import java.io.*;
import java.util.Scanner;
public class ThreadServerSend implements Runnable {
String d;
Socket s1 = null;
Scanner sc = new Scanner(System.in);
public ThreadServerSend(Socket s)
{
    s1=s;
}

public void run()
{
    System.out.println("input msg to send client: ");
    while (true){
    try{

        PrintStream p = new PrintStream(s1.getOutputStream());
    System.out.println("you: ");

                                d=sc.nextLine();
                                p.println(d);
                                if (d.charAt(d.length()-1)=='.'){
                            s1.close();
                            break;}
    }
    catch(IOException e){}
    }
    }
}



import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintStream;
import java.net.Socket;
import java.util.Scanner;

public class ThreadServerReceive implements Runnable {

 String m;
Socket s2 = null;
Scanner sc = new Scanner(System.in);
public ThreadServerReceive(Socket s)
{
    s2=s;
}

public void run()
{
    while (true){
    try{

     BufferedReader b = new BufferedReader(new InputStreamReader(s2.getInputStream()));
        m = b.readLine();
                        System.out.println("client: "+m);

                        if (m.charAt(m.length()-1)=='.'){
                            s2.close();
                            break;}}
    catch(IOException e){}
    }
    }
}




import java.io.*;
import java.net.*;
import java.util.*;
public class Server {

public static void main(String[] args) throws UnknownHostException, IOException{
    // TODO Auto-generated method stub


    ServerSocket s = new ServerSocket(444);

            Socket s1 = s.accept();

            new Thread(new ThreadServerSend(s1)).start();
            ServerSocket s4 = new ServerSocket(443);
    Socket s2=s4.accept();
    new Thread(new ThreadServerReceive(s2)).start();



}
}



import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintStream;
import java.net.Socket;
import java.util.Scanner;
public class ThreadClientSend implements Runnable {

 String d;
Socket s1 = null;
Scanner sc = new Scanner(System.in);
public ThreadClientSend(Socket s)
{
    s1=s;
}

public void run()
{
    System.out.println("Input msg to send server: ");
    while (true){
    try{

        PrintStream p = new PrintStream(s1.getOutputStream());

    System.out.println("you: ");
    String d = new Scanner(System.in).nextLine();



    p.println(d);
            if (d.charAt(d.length()-1)=='.'){
                            s1.close();
                            break;}
      }
    catch(IOException e){}
    }
    }

}


import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintStream;
import java.net.Socket;
import java.util.Scanner;
public class ThreadClientReceive implements Runnable {

 String m;
Socket s1 = null;
Scanner sc = new Scanner(System.in);
public ThreadClientReceive (Socket s)
{
    s1=s;
}

public void run()
{
    while (true){
    try{
        BufferedReader b = new BufferedReader(new InputStreamReader(s1.getInputStream()));
        m= b.readLine();
        System.out.println("Server: "+m);
                     if (m.charAt(m.length()-1)=='.')
                        {
                            s1.close();
                              break;  
                        }
      }
    catch(IOException e){}
    }
    }

}


import java.io.*;
import java.net.*;
import java.util.*;
public class Client {

public static void main(String[] args) throws UnknownHostException, IOException{
    // TODO Auto-generated method stub


    Socket s1= new Socket("localhost",444);
            Socket s2 = new Socket("localhost",443);
            new Thread(new ThreadClientReceive(s1)).start();

    new Thread(new ThreadClientSend(s2)).start();




}

}

Answer 1

A bit late, but I actually came up with a working version of this chat client for my programming class. I thought I might as well post it here. I used TCP (full duplex) with multithreading, and I got it to work in console. The small problem is that you can't see your own name (because console has only one active line), but otherwise it works pretty well.

Server (client is more or less the same, obviously the Sockets are normal sockets, not ServerSockets ):

import java.net.*;
import javax.swing.*;
import java.awt.*;
import java.util.*;
import java.io.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.awt.image.*;


@SuppressWarnings("serial")
public class serverProgII extends Thread
{

private static ObjectOutputStream oos;
private static ObjectInputStream ois;
private static Socket connection;
private static ServerSocket server;
private static String ip, clientIP, textin, exitword ="exit";
private static networkmessage nmessage;
private static boolean connected = false;
private static boolean done = false;
private static String myName = "";
private static int counter = 0;

public static boolean started = false;
public String type;

public static void main(String[] args)
{
    try {
        BufferedReader brin = new BufferedReader(new InputStreamReader(System.in));
        System.out.print("Enter your name:> "); //send prompt to DOS window
        myName = brin.readLine();       //read in user input
        setupConnection();
        setupStreams();
        started = true;
    } catch (Exception e) {
        System.out.println("Problem setting up streams and connection!");
    }

    serverProgII sender = new serverProgII("sender");
    serverProgII receiver = new serverProgII("receiver");
    sender.start();
    receiver.start();
}

public serverProgII(String t)
{
    super();
    type = t;
}

public void run() {
    while(started) {
        switch(type) {
            case "sender":
                sender();
                break;
            case "receiver":
                receiver();
                break;
        }
        try {
            Thread.sleep(500); //milliseconds
        } catch(Exception e){}
    }   
}

/*  runServer()
    This is where all the actual work gets done.
*/

public void sender()
{
    try {

        BufferedReader inn = new BufferedReader(new InputStreamReader(System.in));
        textin = inn.readLine();

        sendData(textin);

        if (textin.equals(exitword))  // if "exit" is typed in shutdown the server.
        {
            started = false;
            serverShutdown();
        }

    }
    catch (Exception e) {
        e.printStackTrace();
    }
}

public void receiver() {
    try {
        getData();
    } catch(Exception e) {
        System.out.println("Error getting data");
    }
}


//setup connection
public static void setupConnection() throws IOException
{
    System.out.println("SERVER MODE ACTIVATED");
    server = new ServerSocket (8000);                       //create the socket at port 8000
    System.out.println("Waiting For Connection...");
    connection = server.accept();                           //wait for a connection
    System.out.println("Received connection: "+connection.getInetAddress());
    clientIP=""+connection.getInetAddress();                //print out the client IP address

}//setupconnection()

//Setup streams connection
public static void setupStreams() throws IOException
{
    //Open up Streams
    System.out.println("Streams Setup");
    oos=new ObjectOutputStream(connection.getOutputStream()); //construct object output stream
    ois=new ObjectInputStream(connection.getInputStream());
    oos.flush();

}//setupStreams()


//method to write/send network data
public void sendData(String toSend) throws IOException
{
    try
    {
        nmessage = new networkmessage(myName, toSend);
        oos.writeObject(nmessage);
    }//try

    catch (IOException ioException)
    {
        System.out.println("IO exception in sendData");
    }

}//sendData()

//method to read in network data
public void getData() throws IOException
{
    try
    {
        networkmessage messageIn =(networkmessage)(ois.readObject());
        System.out.println(messageIn.ipnum +" << "+messageIn.text);

    }//try

    catch (Exception exp1)
    {
        System.out.println("IO exception in sendData");
    }
}//getData()


public void serverShutdown()
{
    System.out.println("exiting initiated");

    try
    {
        done = true;
        textin = "Chat is terminated.  Have a nice day.";
        oos.close();
        server.close();
        connection.close();
    }

    catch (Exception One)
    {
        System.out.println("bad termination");
    }
}


}  // class serverProg