NIO - 多人聊天室Demo代码

package com.xu.nio;

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

/**
 * @author jiafupeng
 * @desc
 * @create 2021/3/7 19:11
 * @update 2021/3/7 19:11
 **/
public class NioServer {

    /**
     * 启动
     */
    public void start() throws IOException {
        // 1. 创建Selector
        Selector selector = Selector.open();
        // 2. 通过ServerSocketChannel创建channel通道
        ServerSocketChannel serverSocketChannel = ServerSocketChannel.open();
        // 3. 为channel通道绑定监听端口
        serverSocketChannel.bind(new InetSocketAddress(8000));
        // 4. 设置channel为非阻塞模式
        serverSocketChannel.configureBlocking(false);
        // 5. 将channel注册到selector上，监听连接事件
        serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);
        System.out.println("服务器启动成功");
        // 6. 循环等待新接入的连接
        for(;;){
            // 阻塞 - 获取可用channel数量
            int readyChannels = selector.select();
            if(readyChannels == 0){continue;}
            // 获取可用channel的集合
            Set<SelectionKey> selectionKeys = selector.selectedKeys();
            Iterator<SelectionKey> iterator = selectionKeys.iterator();
            while (iterator.hasNext()){
                // selectionKey实例
                SelectionKey selectionKey = iterator.next();
                // 移除
                iterator.remove();
                // 7. 根据就绪状态，调用对应方法处理业务逻辑
                // 如果是 接入事件
                if(selectionKey.isAcceptable()){
                    acceptHandler(selectionKey, selector);
                }
                // 如果是 可读事件
                if(selectionKey.isReadable()){
                    readHandler(selectionKey, selector);
                }
            }
        }
    }

    /**
     * 接入事件处理器
     */
    private void acceptHandler(SelectionKey selectionKey,
                               Selector selector)
            throws IOException {
        ServerSocketChannel serverSocketChannel = (ServerSocketChannel)selectionKey.channel();
        // 要是接入事件，创建socketChannel
        SocketChannel socketChannel = serverSocketChannel.accept();
        // 将socketChannel设置为非阻塞工作模式
        socketChannel.configureBlocking(false);
        // 将channel注册到selector上，监听可读事件
        socketChannel.register(selector, SelectionKey.OP_READ);
        // 回复客户端提示信息
         socketChannel.write(Charset.forName("UTF-8").encode("<==== 欢迎进入聊天室 ====>"));
    }

    /**
     * 可读事件处理器
     */
    private void readHandler(SelectionKey selectionKey,
                             Selector selector)
            throws IOException {
        // 要从 selectionKey 中获取已经就绪的channel
        SocketChannel socketChannel = (SocketChannel)selectionKey.channel();
        // 创建buffer
        ByteBuffer byteBuffer = ByteBuffer.allocate(1024);
        // 循环读取客户端请求信息
        String request = "";
        while (socketChannel.read(byteBuffer) > 0){
            // 切换buffer为读模式
            byteBuffer.flip();
            // 读取buffer中的内容
            request += Charset.forName("UTF-8").decode(byteBuffer);
        }
        // 将channel再次注册到selector上，监听其他的可读事件
        socketChannel.register(selector, SelectionKey.OP_READ);
        // 将客户端发送的请求信息 广播给其他客户端
        if(request.length() > 0){
            broadCast(selector, socketChannel, request);
        }
    }

    private void broadCast(Selector selector,
                           SocketChannel sourceChannel, String request){
        Set<SelectionKey> selectionKeySet = selector.keys();
        selectionKeySet.stream().forEach(selectionKey -> {
            Channel targetChannel = selectionKey.channel();

            // 剔除发消息的客户端
            if (targetChannel instanceof SocketChannel
                    && targetChannel != sourceChannel) {
                try {
                    // 将信息发送到targetChannel客户端
                    ((SocketChannel) targetChannel).write(
                            Charset.forName("UTF-8").encode(request));
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        });
    }

    public static void main(String[] args) throws IOException {
        NioServer nioServer = new NioServer();
        nioServer.start();
    }
}

package com.xu.nio;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.nio.charset.Charset;
import java.util.Scanner;

/**
 * @author jiafupeng
 * @desc
 * @create 2021/3/7 19:42
 * @update 2021/3/7 19:42
 **/
public class NioClient {

    private String nickname;

    public NioClient(String nickname) {
        this.nickname = nickname;
    }

    public void start() throws IOException {
        // 连接服务器端
        SocketChannel socketChannel = SocketChannel.open(new InetSocketAddress("127.0.0.1", 8000));

        // 接受服务端响应
        Selector selector = Selector.open();
        socketChannel.configureBlocking(false);
        socketChannel.register(selector, SelectionKey.OP_READ);
        new Thread(new NioClientHandler(selector)).start();

        // 向服务器端发送数据
        Scanner scanner = new Scanner(System.in);
        while (scanner.hasNextLine()){
            String request = scanner.nextLine();
            if(request != null && request.length() > 0){
                socketChannel.write(Charset.forName("UTF-8").encode(nickname + " : " + request));
            }
        }
    }
}

package com.xu.nio;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.nio.charset.Charset;
import java.util.Iterator;
import java.util.Set;

/**
 * @author jiafupeng
 * @desc
 * @create 2021/3/8 10:14
 * @update 2021/3/8 10:14
 **/
public class NioClientHandler implements Runnable {

    private Selector selector;

    public NioClientHandler(Selector selector) {
        this.selector = selector;
    }

    @Override
    public void run() {
        try {
            for (;;) {
                int readyChannels = selector.select();
                if (readyChannels == 0) {continue;}
                Set<SelectionKey> selectionKeys = selector.selectedKeys();
                Iterator iterator = selectionKeys.iterator();
                while (iterator.hasNext()) {
                    SelectionKey selectionKey = (SelectionKey) iterator.next();
                    iterator.remove();
                    if (selectionKey.isReadable()) {
                        readHandler(selectionKey, selector);
                    }
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private void readHandler(SelectionKey selectionKey, Selector selector) throws IOException {
        SocketChannel socketChannel = (SocketChannel) selectionKey.channel();
        ByteBuffer byteBuffer = ByteBuffer.allocate(1024);
        String response = "";
        while (socketChannel.read(byteBuffer) > 0) {
            // 切换buffer为读模式
            byteBuffer.flip();
            // 读取buffer中的内容
            response += Charset.forName("UTF-8").decode(byteBuffer);
        }
        // 将channel再次注册到selector上，监听他的可读事件
        socketChannel.register(selector, SelectionKey.OP_READ);
        // 将服务器端响应信息打印到本地
        if (response.length() > 0) {
            System.out.println(response);
        }

    }
}

package com.xu.nio;

import java.io.IOException;

/**
 * @author jiafupeng
 * @desc
 * @create 2021/3/8 10:59
 * @update 2021/3/8 10:59
 **/
public class XXClient {

    public static void main(String[] args) throws IOException {
        new NioClient("jiafupeng").start();
    }
}

package com.xu.nio;

import java.io.IOException;

/**
 * @author jiafupeng
 * @desc
 * @create 2021/3/8 10:59
 * @update 2021/3/8 10:59
 **/
public class YYClient {

    public static void main(String[] args) throws IOException {
        new NioClient("wangdongxu").start();
    }
}