[JAVA100 example]051, datagram newsletter: Chat bar

FileName: Chatclient.java


import java.net.*;


import java.io.*;


/**


* <p>title: Network chat bar </p>


* <p>description: This is a client of the chat program using datagram communication </p>


* <p>copyright:copyright (c) 2003</p>


* <p>Filename:ChatClient.java</p>


* @version 1.0


*/


public class chatclient{


private Datagramsocket S;


private inetaddress hostaddress;


private byte[] buf = new byte[1000];


Private Datagrampacket DP = new Datagrampacket (buf,buf.length);


/**


*<br> Method Description: constructor, where the implementation receives user input and communicates with the server


*<br> input Parameters:


*<br> return type:


*/


public chatclient () {


try{


//using the constructor to create a packet socket with any available port on the native


s = new Datagramsocket ();


//Get local IP


hostaddress = inetaddress.getbyname ("localhost");


System.out.println ("Client start .... ...");


while (true) {


String outmessage = "";


//Read input


BufferedReader stdin = new BufferedReader (new InputStreamReader (system.in));


try{


outmessage = Stdin.readline ();


}catch (IOException IE) {


System.err.println ("IO error!");


　　　　 }


///If input "bye" means exiting the program


if (outmessage.equals ("Bye")) break;


String outstring = "Client say:" + outmessage;


byte[] buf = Outstring.getbytes ();


//packaging data, sending data


Datagrampacket out = new Datagrampacket (buf,buf.length,hostaddress,chatserver.port);


S.send (out);


//Waiting for server to return


S.receive (DP);


String Rcvd = "Rcvd from" + dp.getaddress () + "," + dp.getport () +


":" + New String (Dp.getdata (), 0,dp.getlength ());


System.out.println (RCVD);





　　　}


}catch (unknownhostexception e) {


System.out.println ("Can;t open socket");


system.exit (1);


}catch (socketexception e) {


System.out.println ("Can;t open socket");


E.printstacktrace ();


system.exit (1);


}catch (IOException e) {


System.err.println ("Communication error");


E.printstacktrace ();


system.exit (1);


}catch (Exception e) {


System.err.println ("Communication error");


E.printstacktrace ();


system.exit (1);


　　 }


System.out.println ("ChatClient over");


}


/**


*<br> Method Description: Main method


*<br> input Parameters:


*<br> return type:


*/


public static void Main (string[] args) {


new ChatClient ();


}


}


import java.net.*;


import java.io.*;


import java.util.*;


/**


* <p>title: Network chat bar </p>


* <p>description: Chat servers created using datagrams </p>


* <p>copyright:copyright (c) 2003</p>


* <p>Filename:ChatServer.java</p>


* @version 1.0


*/


public class chatserver{


static final int port = 4000;//Set Service port


private byte[] buf = new byte[1000];


private Datagrampacket DGP =new datagrampacket (buf,buf.length);


Private Datagramsocket SK;


/**


*<br> Method Description: Server-side constructor, to achieve read user input and communication


*<br> input Parameters:


*<br> return type:


*/


public Chatserver () {


try{


//Materialized datagram


SK = new Datagramsocket (PORT);


System.out.println ("Server start ... .... ..."), and the;


while (true) {


//Waiting to receive


sk.receive (DGP);


//Get receive information


String rcvd = new String (Dgp.getdata (), 0,dgp.getlength ()) +


", From Address:" + dgp.getaddress () +


", Port:" + dgp.getport ();


System.out.println (RCVD);


String outmessage = "";


//Read input


BufferedReader stdin = new BufferedReader (new InputStreamReader (system.in));


try{


outmessage = Stdin.readline ();


}catch (IOException IE) {


System.err.println ("IO error!");


　　　　 }


String outstring = "Server say:" + outmessage;


//Copy characters to cache


byte[] buf = Outstring.getbytes ();


//package data, send back information.


Datagrampacket out = new Datagrampacket (buf,buf.length,dgp.getaddress (), Dgp.getport ());


Sk.send (out);


　　 }


}catch (socketexception e) {


System.err.println ("Can´t open socket");


system.exit (1);


}catch (IOException e) {


System.err.println ("Communication error");


E.printstacktrace ();


system.exit (1);


　　}


}


public static void Main (string[] args) {


new Chatserver ();


}


}