Multi-User chat implemented in java (console input)

I don't know how to do it when I want to create a multi-person chat room while learning android.

I want to make a simple multi-person chat room with pure java.

Data transmission through Socket

Knowledge points used: Socket, ServerSocket, and Multithreading

 

Server program:

Import java. io. bufferedReader; import java. io. IOException; import java. io. inputStream; import java. io. inputStreamReader; import java. io. outputStream; import java. io. printWriter; import java.net. serverSocket; import java.net. socket; import java.net. URLDecoder; import java.net. unknownHostException; import java. util. arrayList; // This program is a connected program, commonly known as a server program // In the program world, the network refers to the interaction of information between two programs, therefore, the network must contain more than two programs. One end is called a server and the other is called a client. The correspondence with the client is 1-Npublic class SimpleServer {// used to save the public static ArrayList of the currently connected user <Socket> socketList = new ArrayList <Socket> (); public static void main (String [] args) throws Exception {// create a serverSocket to listen to the client Socket connection request ServerSocket serverSocket = new ServerSocket (10002 ); // 10002 the port number for this server: System. out. println ("service start"); // uses a loop to continuously receive requests from the client while (true) {// whenever a request from the client is received, the server also generates a SocketSocket socket = serverSocket. Accept (); System. out. println ("service connection"); // Add the connected client to the socketList in the list. add (socket); // start a new thread // task thread, each connection has a dedicated Task thread // This thread will process the message sending and response new MyThread (socket, socketList ). start ();}/* BufferedReader br = new BufferedReader (new InputStreamReader (System. in); PrintWriter pw = new PrintWriter (socket. getOutputStream (), true); // output the input content to clientwhile (true) {String msg = br. readLine (); pw. println ("server:" + msg) ;} */} Class MyThread extends Thread {Socket client; ArrayList <Socket> clients; BufferedReader br; public MyThread (Socket client, ArrayList <Socket> clients) throws Exception {super (); this. client = client; this. clients = clients; br = new BufferedReader (new InputStreamReader (this. client. getInputStream ();} // send the received message to the public void run () {try {String content = null; while (true) {// read information from a client if (content = br. re AdLine ())! = Null) {for (Socket socket: clients) {if (client! = Socket) {// send the read message to the PrintWriter pw = new PrintWriter (socket. getOutputStream (), true); pw. println (content) ;}} content = URLDecoder. decode (content, "UTF-8"); System. out. println (content) ;}} catch (IOException e) {// TODO Auto-generated catch blocke. printStackTrace ();}}}

Client Program:

Import java. io. bufferedReader; import java. io. IOException; import java. io. inputStream; import java. io. inputStreamReader; import java. io. printWriter; import java.net. socket; import java.net. URLDecoder; import java.net. URLEncoder; public class Client {/*** @ param args */public static void main (String [] args) throws Exception {// TODO Auto-generated method stub // create a socketSocket client Connected to the Local Machine with port 10002 = new Socket ("192.168.3.26", 10002); new MyThread (client ). start (); InputStream is = client. getInputStream (); BufferedReader br = new BufferedReader (new InputStreamReader (is); while (true) {String msg = br. readLine (); // decodes the received information. msg = URLDecoder. decode (msg, "UTF-8"); System. out. println (msg) ;}} class MyThread extends Thread {Socket client; public MyThread (Socket client) {super (); this. client = client;} public void run () {// send a message try {BufferedReader br = new BufferedReader (new InputStreamReader (System. in); PrintWriter pw = new PrintWriter (client. getOutputStream (), true); // output the input content to socketwhile (true) {String msg = br. readLine (); // encode the sent message msg = URLEncoder. encode ("Zhang San said:" + msg, "UTF-8"); pw. println (msg) ;}} catch (IOException e) {// TODO Auto-generated catch blocke. printStackTrace ();}}}

This is just a design concept, a little simple, and can only send and receive messages from the console