JavaNIO手写聊天室

服务端

package com.huwc.nio;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.*;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;

public class ChatServer {

    private Selector selector ;

    private ServerSocketChannel serverChannel ;

    private static final int PORT = 6666 ;

    private Map<SocketChannel, String> usernameMap = new HashMap<>();

    public ChatServer() {
        try {
            selector = Selector.open();
            serverChannel = ServerSocketChannel.open();
            serverChannel.configureBlocking(false) ;
            serverChannel.bind(new InetSocketAddress(PORT));
            serverChannel.register(selector, SelectionKey.OP_ACCEPT);
            listen();
            return;
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public void listen() {
        while (true){
            int count = 0;
            try {
                count = selector.select();
            } catch (IOException e) {
                e.printStackTrace();
            }
            if(count > 0){
                Set<SelectionKey> keys = selector.selectedKeys();
                Iterator<SelectionKey> iterator = keys.iterator();
                while(iterator.hasNext()){
                    SelectionKey selectionKey = iterator.next();
                    if(selectionKey.isAcceptable()){
                        try {
                            SocketChannel socketChannel = serverChannel.accept();
                            socketChannel.configureBlocking(false);
                            socketChannel.register(selector, SelectionKey.OP_READ, ByteBuffer.allocate(1024));
                            System.out.println(socketChannel.getRemoteAddress() + " 上线了");
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }

                    if(selectionKey.isReadable()){
                        SocketChannel socketChannel = (SocketChannel) selectionKey.channel();
                        try {
                            ByteBuffer buffer = (ByteBuffer) selectionKey.attachment();
                            buffer.clear();
                            int readCount = socketChannel.read(buffer);
                            buffer.flip();
                            if(readCount > 0){
                                String message = new String(buffer.array(), 0, buffer.limit());
                                if(message.startsWith("name:")){
                                    String username = message.replaceAll("name:","");
                                    usernameMap.put(socketChannel, username);
                                    transferMessage(socketChannel.getRemoteAddress()+" 改名为：" + username, socketChannel);
                                }else {
                                    //转发给所有的客户端
                                    transferMessage(message, socketChannel);
                                }
                            }
                        } catch (IOException e) {
                            try {
                                System.out.println(socketChannel.getRemoteAddress().toString().substring(1) + " 下线了");
                                selectionKey.cancel();
                                socketChannel.close();
                            } catch (IOException ex) {
                                ex.printStackTrace();
                            }
                        }
                    }

                    iterator.remove();
                }
            }else {

            }
        }
    }

    private void transferMessage(String message, SocketChannel selfChannel) throws IOException {
        Set<SelectionKey> keys = selector.keys();
        for (SelectionKey key : keys) {
            Channel channel = key.channel();
            if(channel instanceof SocketChannel && channel != selfChannel){
                String username = usernameMap.get(selfChannel);
                if(null == username || username.equals("")){
                    username = ((SocketChannel) channel).getRemoteAddress().toString().substring(1);
                }
                String msg = username + " 说: " + message ;
                ByteBuffer buffer = ByteBuffer.wrap(msg.getBytes());
                try {
                    ((SocketChannel) channel).write(buffer);
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    public static void main(String[] args) throws IOException {
        ChatServer server = new ChatServer();
        server.listen();
    }
}

客户端

package com.huwc.nio;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
import java.util.Scanner;
import java.util.Set;

public class ChatClient {

    private final String HOST = "127.0.0.1" ;

    private final int PORT = 6666 ;

    private Selector selector ;

    private SocketChannel socketChannel ;

    private String username ;

    public ChatClient() {
        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 (IOException e) {
            e.printStackTrace();
        }
    }

    public void sendInfo(String info){
        try {
            socketChannel.write(ByteBuffer.wrap(info.getBytes()));
        }catch (IOException e){

        }
    }

    public void readInfo(){
        try {
            int count = selector.select();
            if(count > 0){
                Set<SelectionKey> keys = selector.selectedKeys();
                Iterator<SelectionKey> iterator = keys.iterator();
                while(iterator.hasNext()){
                    SelectionKey key = iterator.next();
                    if(key.isReadable()){
                        SocketChannel channel = (SocketChannel) key.channel();
                        ByteBuffer buffer = ByteBuffer.allocate(1024);
                        channel.read(buffer);
                        String msg = new String(buffer.array(), 0, buffer.limit());
                        System.out.println(msg.trim());
                    }

                    iterator.remove();
                }
            }else {

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

    public static void main(String[] args) {
        ChatClient client = new ChatClient();
        //启动一个线程，进行数据的读取
        Thread thread = new Thread(){
            @Override
            public void run() {
                while (true){
                    client.readInfo();
                    try {
                        Thread.currentThread().sleep(3000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        };
        thread.start();

        //发送数据
        Scanner scanner = new Scanner(System.in) ;
        while (scanner.hasNextLine()){
            String msg = scanner.nextLine();
            client.sendInfo(msg);
        }
    }
}

测试截图