Java -- & gt; implements the group chat function (C/S mode -- TCP protocol), java ---- tcp

Java --> implement the group chat function (C/S mode -- TCP protocol), java ---- tcp

--> Java supports TCP:

--> The java.net package defines two types of ServerSocket and Socket, which are used to implement two-way connection between the server and client respectively.

--> Client class definition Client

Package com. dragon. java. tcpchat; import java. io. IOException; import java.net. socket; import java.net. unknownHostException;/*** Client ** @ author Auser **/public class Client {public static void main (String args []) throws UnknownHostException, IOException {Socket client = new Socket ("192.168.1.188", 10000); // new ClientSend (client) thread that sends the information of the wearable device ). start (); // create the thread for receiving information new ClientReceive (client ). start ();
// The output stream and client cannot be closed because the chat function is implemented instead of sending information only once. // Client. shutdownOutput (); // client. close ();}}

--> The ClientSend class defines the thread in which the client sends information to the server.

Package com. dragon. java. tcpchat; import java. io. IOException; import java. io. printStream; import java.net. socket; import java. util. threads;/*** the Thread from which the client sends messages to the server ** @ author Auser **/public class ClientSend extends Thread {private sockets; private Socket socket; public ClientSend (Socket socket) {this. socket = socket ;}@ Override public void run () {response = new response (System. in); try {PrintS Tream ps = new PrintStream (socket. getOutputStream (); String line = ""; // blocked message sending while (line = response. nextLine ())! = Null) {ps. println (line) ;}} catch (IOException e) {e. printStackTrace ();}}}

--> The ClientReceive class defines the thread in which the client receives server information.

Package com. dragon. java. tcpchat; import java. io. bufferedReader; import java. io. inputStreamReader; import java.net. socket;/*** Thread for receiving information from the client ** @ author Auser **/public class ClientReceive extends Thread {private Socket socket; public ClientReceive (Socket socket Socket) {this. socket = socket ;}@ Override public void run () {try {BufferedReader br = new BufferedReader (new InputStreamReader (socket. getInputSt Ream (); // receives information by line String line = ""; while (line = br. readLine ())! = Null) {System. out. println (line) ;}} catch (Exception e) {e. printStackTrace ();}}}

--> Server class definition Server

Package com. dragon. java. tcpchat; import java. io. IOException; import java.net. serverSocket; import java.net. socket; import java. util. arrayList; import java. util. list;/*** Server ** @ author Auser **/public class Server {public static void main (String [] args) throws IOException, interruptedException {List <Socket> list = new ArrayList <> (); // create a server Socket ServerSocket server = new ServerSocket (10000); while (True) {// method of blocking the receiving client Socket = server. accept (); // It is designed that multiple threads may add or delete the set. synchronous processing of synchronized (list) {list. add (socket) ;}// start a new thread to process the communication between the client, new HandleSocket (socket, list ). start () ;}// because the client does not know when to send the message, the server must be enabled and cannot be closed. }}

--> HandleSocket class is used to operate clients connected to the server (online/offline notifications, blocking and blacklisting, and sending information to each client, etc ...)

Package com. dragon. java. tcpchat; import java. io. bufferedReader; import java. io. IOException; import java. io. inputStreamReader; import java. io. printStream; import java.net. inetAddress; import java.net. socket; import java. util. list;/*** process the Thread of each (single) Client Connected to the server ** @ author Auser **/public class HandleSocket extends Thread {private Socket socket; private List <Socket> list;/***** constructor ** @ param socket * currently connected Client * @ param list * stores the set of connected clients */public HandleSocket (Socket socket, List <Socket> list) {this. socket = socket; this. list = list;}/*** thread run Method */@ Override public void run () {InetAddress address = socket. getInetAddress (); // obtain the address of the client connected to the Server String ip = address. getHostAddress (); System. out. println (ip + "launched! "); If (ip. equals (" 192.168.1.117 ") {synchronized (list) {sendToAll (ip +" has been blacklisted due to illegal operations! "); List. remove (socket) ;}return ;}try {BufferedReader br = new BufferedReader (new InputStreamReader (socket. getInputStream (), "gbk"); String line = ""; while (line = br. readLine ())! = Null) {String msg = ip + ":" + line; System. out. println (msg); // output to the console of the server // send what the client says to all other clients sendToAll (msg) ;}} catch (IOException e) {// e. printStackTrace (); System. out. println (ip + "offline! "); Synchronized (list) {list. remove (socket) ;}}/ *** send the information to all clients, remove the information sent by the current socket ** @ param msg */private void sendToAll (String msg) {synchronized (list) {for (Socket s: list) {if (s! = Socket) {try {PrintStream ps = new PrintStream (s. getOutputStream (); ps. println ();} catch (IOException e) {e. printStackTrace ();}}}}}}

--> Note: To connect the client to the server, you must first find the server. Therefore, the server must be enabled before enabling the server...

--> This is a weak LAN chat function...