一、基於上節編寫基礎聊天

GroupChatServer

package com.github.bjlhx15.netty.demo.groupchat;

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

public class GroupChatServer {
    private Selector selector;
    private
 
 ServerSocketChannel listenerChannel;
    private static final int PORT = 6667;

    public GroupChatServer() {
        try {
            selector = Selector.open();
            listenerChannel = ServerSocketChannel.open();
            listenerChannel.bind(new InetSocketAddress(PORT));
            listenerChannel.configureBlocking(
 
false);
            listenerChannel.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
 
<SelectionKey> iterator = selector.selectedKeys().iterator();
                    while (iterator.hasNext()) {
                        SelectionKey key = iterator.next();
                        if (key.isAcceptable()) {
                            SocketChannel socketChannel = listenerChannel.accept();
                            socketChannel.configureBlocking(false);
                            socketChannel.register(selector, SelectionKey.OP_READ);
                            System.out.println(socketChannel.getRemoteAddress() + " 上線");
                        }
                        if (key.isReadable()) {
                            readData(key);
                        }
                        //刪除key防止重複處理
                        iterator.remove();
                    }
                } else {
                    System.out.println("waiting……");
                }

            }
        } 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());
                System.out.println("from 客戶端 " + msg);
                //向其他客戶端轉發訊息
                sendInfoToOtherClient(msg, channel);
            }
        } catch (IOException e) {
            try {
                System.out.println(channel.getRemoteAddress() + " 離線了");
                key.cancel();
                channel.close();
            } catch (IOException ioException) {
                ioException.printStackTrace();
            }
        }
    }

    //    轉發訊息給其他客戶（即通道）
    private void sendInfoToOtherClient(String msg, SocketChannel self) throws IOException {
        System.out.println("伺服器轉發訊息");
        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());

                dest.write(buffer);
            }
        }
    }

    public static void main(String[] args) {
        GroupChatServer groupChatServer = new GroupChatServer();
        groupChatServer.listen();
    }
}

GroupChatClient

package com.github.bjlhx15.netty.demo.groupchat;

import sun.jvm.hotspot.oops.ByteField;

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.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.util.Iterator;
import java.util.Scanner;

public class GroupChatClient {
    private final String HOST = "127.0.0.1";
    private final int PORT = 6667;
    private Selector selector;
    private SocketChannel socketChannel;
    private String username;

    public GroupChatClient() throws IOException {
        selector = this.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^……");
    }

    public void sendInfo(String info) {
        info = username + " 說：" + info;

        try {
            socketChannel.write(ByteBuffer.wrap(info.getBytes()));
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public void readInfo() {
        try {
            int readChannels = selector.select();
            if (readChannels > 0) {
                Iterator<SelectionKey> iterator = selector.selectedKeys().iterator();
                while (iterator.hasNext()) {
                    SelectionKey key = iterator.next();
                    if (key.isReadable()) {
                        SocketChannel sc = (SocketChannel) key.channel();
                        ByteBuffer buffer = ByteBuffer.allocate(1024);
                        sc.read(buffer);
                        String msg = new String(buffer.array());
                        System.out.println(msg.trim());
                    }
//                    key.cancel();
                    iterator.remove();
                }
            } else {
//                System.out.println("沒有可用通道");
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) throws Exception {
        GroupChatClient chatClient = new GroupChatClient();
        new Thread() {
            @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);
        }
    }
}