Java群聊服务器与客户端实现

服务器端实现

以下是群聊服务器的核心实现代码，基于Java NIO的非阻塞IO模型。

public class GroupChatServer {    private Selector selector;    private ServerSocketChannel listenChannel;    private static final int PORT = 6666;    public GroupChatServer() {        try {            selector = Selector.open();            listenChannel = ServerSocketChannel.open();            listenChannel.socket().bind(new InetSocketAddress(PORT));            listenChannel.configureBlocking(false);            listenChannel.register(selector, SelectionKey.OP_ACCEPT);        } catch (IOException e) {            e.printStackTrace();        }    }    public void listen() {        try {            while (true) {                int count = selector.select(2000);                if (count > 0) {                    Iterator
   
     iterator = selector.selectedKeys().iterator();                    while (iterator.hasNext()) {                        SelectionKey key = iterator.next();                        if (key.isAcceptable()) {                            SocketChannel socketChannel = listenChannel.accept();                            socketChannel.configureBlocking(false);                            socketChannel.register(selector, SelectionKey.OP_READ);                            System.out.println(socketChannel.getRemoteAddress() + " 客户端 上线");                        }                        if (key.isReadable()) {                            readData(key);                        }                        iterator.remove();                    }                }            }        } catch (Exception e) {            e.printStackTrace();        } finally {        }    }    private void readData(SelectionKey key) {        SocketChannel channel = null;        try {            channel = (SocketChannel) key.channel();            ByteBuffer buffer = ByteBuffer.allocate(1024);            int count = channel.read(buffer);            if (count > 0) {                String msg = new String(buffer.array(), "GBK");                System.out.println("from 客户端：" + msg);                sendInfoToOtherClients(msg, channel);            }        } catch (IOException e) {            try {                System.out.println(channel.getRemoteAddress() + " 离线了..");                key.cancel();                channel.close();            } catch (IOException ioException) {                ioException.printStackTrace();            }        }    }    private void sendInfoToOtherClients(String msg, SocketChannel self) throws IOException {        System.out.println("服务器转发消息中...");        for (SelectionKey key : selector.keys()) {            Channel targetChannel = key.channel();            if (targetChannel instanceof SocketChannel && targetChannel != self) {                SocketChannel dest = (SocketChannel) targetChannel;                ByteBuffer buffer = ByteBuffer.wrap(msg.getBytes("GBK"));                dest.write(buffer);            }        }    }    public static void main(String[] args) {        GroupChatServer chatServer = new GroupChatServer();        chatServer.listen();    }}

客户端实现

以下是客户端的实现代码，同样基于Java NIO的非阻塞IO模型。

public class GroupChatClient {    private final String HOST = "127.0.0.1";    private final int PORT = 6666;    private Selector selector;    private SocketChannel socketChannel;    private String username;    public GroupChatClient() {        try {            selector = Selector.open();            socketChannel = SocketChannel.open(new InetSocketAddress(HOST, PORT));            socketChannel.configureBlocking(false);            socketChannel.register(selector, SelectionKey.OP_READ);            username = socketChannel.getLocalAddress().toString().substring(1);            System.out.println(username + " is ok ...");        } catch (Exception e) {            e.printStackTrace();        }    }    public void sendInfo(String info) {        info = username + " 说：" + info;        try {            socketChannel.write(ByteBuffer.wrap(info.getBytes("GBK")));        } catch (IOException e) {            e.printStackTrace();        }    }    public void readInfo() {        try {            int readChannels = selector.select(2000);            if (readChannels > 0) {                Iterator
   
     iterator = selector.selectedKeys().iterator();                while (iterator.hasNext()) {                    SelectionKey key = iterator.next();                    if (key.isReadable()) {                        SocketChannel socketChannel = (SocketChannel) key.channel();                        ByteBuffer buffer = ByteBuffer.allocate(1024);                        socketChannel.read(buffer);                        String msg = new String(buffer.array());                        System.out.println(msg.trim());                    }                    iterator.remove();                }            }        } catch (IOException e) {            e.printStackTrace();        }    }    public static void main(String[] args) {        GroupChatClient chatClient = new GroupChatClient();        new Thread(new Runnable() {            @Override            public void run() {                while (true) {                    chatClient.readInfo();                    try {                        Thread.currentThread().sleep(3000);                    } catch (InterruptedException e) {                        e.printStackTrace();                    }                }            }        }).start();        Scanner scanner = new Scanner(System.in);        while (scanner.hasNextLine()) {            String s = scanner.nextLine();            chatClient.sendInfo(s);        }    }}