NIO群聊系统

GroupChatServer

package com.guiguixia.nio.groupchat;

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

/**
 * 群聊系统服务端
 * @author wzcstart
 * @date 2021/6/16 - 23:07
 */
public class groupChatServer {
    //Selector - 选择器
    private Selector selector;
    //ServerSocketChannel - 服务端监听器
    private ServerSocketChannel listenChannel;
    //端口号
    private final int PORT = 6667;

    public groupChatServer() {
        try {
            //构造选择器
            selector = Selector.open();
            //构造服务端
            listenChannel = ServerSocketChannel.open();
            //绑定端口
            listenChannel.socket().bind(new InetSocketAddress(PORT));
            //设置非阻塞
            listenChannel.configureBlocking(false);
            //注册服务器监听器
            listenChannel.register(selector, SelectionKey.OP_ACCEPT);
            System.out.println("服务器准备好了");
        }catch (IOException e){
            e.printStackTrace();
        }
    }

    //监听方法
    public void listen(){
        try {
            while (true){
                //监听
                int count = selector.select();
                //判断时候有触发事件
                if (count > 0){
                    //获取触发的selectKey
                    Set<SelectionKey> selectionKeys = selector.selectedKeys();
                    //使用迭代器模式
                    Iterator<SelectionKey> skIterator = selectionKeys.iterator();
                    while (skIterator.hasNext()){
                        //获取当前的selectionKey
                        SelectionKey selectionKey = skIterator.next();
                        //处理连接事件
                        if (selectionKey.isAcceptable()){
                            //接受连接 - 本身此方法为阻塞但是已经发生了连接事件所以将直接获取channel
                            SocketChannel socketChannel = listenChannel.accept();
                            //设置为非阻塞
                            socketChannel.configureBlocking(false);
                            //注册此socketChannel
                            socketChannel.register(selector,SelectionKey.OP_READ);
                            System.out.println(socketChannel.getRemoteAddress() + "上线了");
                        }
                        //处理读事件
                        if (selectionKey.isReadable()){
                            //触发读事件
                            readData(selectionKey);
                        }

                        //移除已经处理过的selectionKey - 防止重复触发
                        skIterator.remove();
                    }
                }else {
                    System.out.println("服务器无响应2s...");
                }
            }
        }catch (Exception e){
            e.printStackTrace();
        }finally {

        }
    }

    //读取数据
    private void readData(SelectionKey sk){

        SocketChannel channel = null;

        try {
            //通过selectionKey获取通道
            channel = (SocketChannel) sk.channel();
            ByteBuffer byteBuffer = ByteBuffer.allocate(1024);
            //读取
            int count = channel.read(byteBuffer);
            if (count>0){
                String msg = new String(byteBuffer.array()).trim();
                System.out.println("from 客户端："+msg);
                //转发消息
                sendInfoToOther(msg,channel);
            }

            //转发 - 向其他channel转发消息

        }catch (IOException e){

            try {
                //取消注册
                sk.cancel();
                //提示下线
                System.out.println("客户端下线"+channel.getRemoteAddress());
                //关闭资源
                channel.close();
            } catch (IOException ioException) {
                ioException.printStackTrace();
            }
            sk.cancel();
        }

    }

    //向其他channel转发消息
    private void sendInfoToOther(String info,SocketChannel self) throws IOException{
        System.out.println("服务器转发消息中...");

        for(SelectionKey sk : selector.keys()){
            SelectableChannel targetChannel = sk.channel();
            if (targetChannel instanceof SocketChannel && targetChannel!=self){
                //得到要转发的目标通道
                SocketChannel dest = (SocketChannel) targetChannel;
                //构建Buffer
                ByteBuffer byteBuffer = ByteBuffer.wrap(info.getBytes());
                //写入到目标通道
                dest.write(byteBuffer);
            }
        }
    }

    public static void main(String[] args){
        //创建服务器
        groupChatServer groupChatServer = new groupChatServer();
        groupChatServer.listen();

    }
}

GroupChatClient

package com.guiguixia.nio.groupchat;

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.concurrent.TimeUnit;

/**
 * 群聊客户端
 *
 * @author wzcstart
 * @date 2021/6/17 - 23:10
 */
public class groupChatClient {
    //服务端ip
    private final String HOST = "127.0.0.1";
    //服务端端口号
    private final int PORT = 6667;
    //客户端通道
    private SocketChannel socketChannel;
    //选择器
    private Selector selector;
    //此客户端名字 - 本地地址
    private String username;

    //构造初始化
    public groupChatClient() {
        try {
            //构建选择器
            selector = Selector.open();
            //构建socketChannel
            socketChannel = SocketChannel.open(new InetSocketAddress(HOST, PORT));
            //设置为非阻塞通道
            socketChannel.configureBlocking(false);
            //注册通道到选择器 - 监听读事件
            socketChannel.register(selector, SelectionKey.OP_READ);
            //获取本客户端地址
            username = socketChannel.getLocalAddress().toString().substring(1);
            System.out.println(username + " is ok...");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    //读服务器转发的消息
    public void readInfo() {

        try {
            //监听事件的发生
            int count = selector.select();
            if (count > 0) {
                //获取触发事件的迭代器
                Iterator<SelectionKey> skIterator = selector.selectedKeys().iterator();
                while (skIterator.hasNext()) {
                    SelectionKey sk = skIterator.next();
                    //判断是否是读事件被触发
                    if (sk.isReadable()) {
                        //获取通道
                        SocketChannel sc = (SocketChannel) sk.channel();
                        //获取消息
                        ByteBuffer byteBuffer = ByteBuffer.allocate(1024);
                        sc.read(byteBuffer);
                        String msg = new String(byteBuffer.array()).trim();
                        System.out.println(msg);
                    }
                    //移除当前触发事件 - 避免重复触发
                    skIterator.remove();
                }

            } else {
                System.out.println("没有可用通道...");
            }

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

    //发送给服务器消息
    public void writeInfo(String info) {

        info = username + " 说：" + info;
        try {
            socketChannel.write(ByteBuffer.wrap(info.getBytes()));
        } catch (IOException e) {
            e.printStackTrace();
        }

    }

    public static void main(String[] args) {

        groupChatClient groupChatClient = new groupChatClient();

        new Thread(() -> {
            while (true) {
                groupChatClient.readInfo();
                try {
                    TimeUnit.SECONDS.sleep(3);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }).start();

        Scanner scanner = new Scanner(System.in);
        while (scanner.hasNextLine()){
            String msg = scanner.nextLine();
            groupChatClient.writeInfo(msg);
        }
    }
}