• 日期: 2024-12-16
  • 标签: 常规

Netty 多人聊天室服务器和客户端代码示例

本示例演示了使用 Netty 框架构建一个简单的多人聊天室服务器和客户端，实现用户登录、聊天室列表、消息发送和私聊等功能。

服务器端代码

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;
import io.netty.util.concurrent.DefaultEventExecutorGroup;
import io.netty.util.concurrent.EventExecutorGroup;

import java.util.concurrent.ConcurrentHashMap;

public class MultiChatServer {
    private final int port;
    private final ConcurrentHashMap<String, ChannelHandlerContext> userMap = new ConcurrentHashMap<>();
    private final EventExecutorGroup group = new DefaultEventExecutorGroup(16);

    public MultiChatServer(int port) {
        this.port = port;
    }

    public void run() throws Exception {
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        try {
            ServerBootstrap b = new ServerBootstrap();
            b.group(bossGroup, workerGroup)
                    .channel(NioServerSocketChannel.class)
                    .childHandler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        public void initChannel(SocketChannel ch) throws Exception {
                            ch.pipeline().addLast(new StringDecoder(), new StringEncoder(), new MultiChatServerHandler(userMap, group));
                        }
                    })
                    .option(ChannelOption.SO_BACKLOG, 128)
                    .childOption(ChannelOption.SO_KEEPALIVE, true);

            ChannelFuture f = b.bind(port).sync();
            System.out.println('Server started on port ' + port);
            f.channel().closeFuture().sync();
        } finally {
            workerGroup.shutdownGracefully();
            bossGroup.shutdownGracefully();
        }
    }

    public static void main(String[] args) throws Exception {
        int port = 8080;
        new MultiChatServer(port).run();
    }
}

客户端代码

package org.example;

import io.netty.bootstrap.Bootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;

import java.io.BufferedReader;
import java.io.InputStreamReader;

public class MultiChatClient {
    private final String host;
    private final int port;
    private ChannelHandlerContext ctx;

    public MultiChatClient(String host, int port) {
        this.host = host;
        this.port = port;
    }

    public void run() throws Exception {
        EventLoopGroup group = new NioEventLoopGroup();
        try {
            Bootstrap b = new Bootstrap();
            b.group(group)
                    .channel(NioSocketChannel.class)
                    .option(ChannelOption.SO_KEEPALIVE, true)
                    .handler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        public void initChannel(SocketChannel ch) throws Exception {
                            ch.pipeline().addLast(new StringDecoder(), new StringEncoder(), new MultiChatClientHandler());
                        }
                    });
            ChannelFuture f = b.connect(host, port).sync();
            ctx = f.channel().pipeline().context(MultiChatClientHandler.class);
            BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
            while (true) {
                String line = in.readLine();
                if (line == null) {
                    break;
                }
                if (line.equals('LIST')) {
                    String username = null;
                    ctx.writeAndFlush(line + '|' + username + '\n');
                } else {
                    ctx.writeAndFlush(line + '\n');
                }
            }
        } finally {
            group.shutdownGracefully();
        }
    }

    public static void main(String[] args) throws Exception {
        String host = 'localhost';
        int port = 8080;
        new MultiChatClient(host, port).run();
    }
}

聊天室处理器 (MultiChatServerHandler)

package org.example;

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.util.concurrent.EventExecutorGroup;

import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

public class MultiChatServerHandler extends SimpleChannelInboundHandler<String> {
    private final ConcurrentHashMap<String, ChannelHandlerContext> userMap;
    private final EventExecutorGroup group;

    public MultiChatServerHandler(ConcurrentHashMap<String, ChannelHandlerContext> userMap, EventExecutorGroup group) {
        this.userMap = userMap;
        this.group = group;
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        System.out.println('Client connected: ' + ctx.channel().remoteAddress());
    }

    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        System.out.println('Client disconnected: ' + ctx.channel().remoteAddress());
        userMap.values().remove(ctx);
    }

    @Override
    protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {
        String[] tokens = msg.split('\\|');
        String command = tokens[0];

        System.out.println('Received message from client: ' + msg);

        switch (command) {
            case 'LOGIN':
                handleLogin(ctx, tokens[1], tokens[2]);
                break;
            case 'LIST':
                handleList(ctx);
                break;
            case 'MSG':
                handleMessage(ctx, tokens[1], tokens[2]);
                break;
            case 'PRIVATE':
                handlePrivateMessage(ctx, tokens[1], tokens[2]);
                break;
            default:
                ctx.writeAndFlush('Invalid command: ' + command);
                break;
        }
    }

    private void handleLogin(ChannelHandlerContext ctx, String username, String password) {
        if (userMap.containsKey(username)) {
            ctx.writeAndFlush('User already logged in: ' + username);
        } else {
            userMap.put(username, ctx);
            ctx.writeAndFlush('Login successful: ' + username);
        }
    }

    private void handleList(ChannelHandlerContext ctx) {
        StringBuilder sb = new StringBuilder();
        sb.append('Available chat rooms:\n');
        for (Map.Entry<String, ChannelHandlerContext> entry : userMap.entrySet()) {
            sb.append(entry.getKey()).append('\n');
        }
        boolean username = false;
        if (userMap.containsKey(username)) {
            sb.append('Your information:\n');
            sb.append(username).append('\n');
        }
        ctx.writeAndFlush(sb.toString());
    }

    private void handleMessage(ChannelHandlerContext ctx, String roomName, String message) {
        StringBuilder sb = new StringBuilder();
        sb.append('[').append(ctx.channel().remoteAddress()).append('] ').append(message).append('\n');
        for (Map.Entry<String, ChannelHandlerContext> entry : userMap.entrySet()) {
            if (entry.getKey().equals(roomName)) {
                entry.getValue().writeAndFlush(sb.toString());
            }
        }
    }

    private void handlePrivateMessage(ChannelHandlerContext ctx, String recipient, String message) {
        StringBuilder sb = new StringBuilder();
        sb.append('[').append(ctx.channel().remoteAddress()).append('] (private) ').append(message).append('\n');
        if (userMap.containsKey(recipient)) {
            userMap.get(recipient).writeAndFlush(sb.toString());
        } else {
            ctx.writeAndFlush('User not found: ' + recipient);
        }
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        cause.printStackTrace();
        ctx.close();
    }
}

客户端消息处理器 (MultiChatClientHandler)

package org.example;

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;

public class MultiChatClientHandler extends SimpleChannelInboundHandler<String> {
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {
        System.out.println(msg);
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        cause.printStackTrace();
        ctx.close();
    }
}

运行和使用

  1. 运行服务器端代码:

    • 在命令行中运行 javac MultiChatServer.java 编译代码
    • 运行 java MultiChatServer 启动服务器

  2. 运行客户端代码:

    • 编译客户端代码: javac MultiChatClient.java
    • 运行客户端代码: java MultiChatClient

  3. 在客户端窗口中进行交互:

    • 客户端会提示输入用户名和密码，请按照提示输入。
    • 登录成功后，客户端会显示可用的聊天室列表。
    • 输入 'LIST' 命令，按下回车键，客户端会显示当前可用的聊天室列表。
    • 输入 'MSG|聊天室名|消息内容' 命令，按下回车键，客户端会将消息发送给指定的聊天室内的所有用户。
    • 输入 'PRIVATE|用户名|消息内容' 命令，按下回车键，客户端会将私聊消息发送给指定的用户。
    • 输入 'EXIT' 命令，按下回车键，客户端会退出程序。

  4. 在服务器端窗口中查看结果:

    • 服务器端会显示客户端的连接和断开信息。
    • 服务器端会显示接收到的消息和发送的消息。

通过以上步骤，可以运行并查看这个代码的聊天功能。

Netty 多人聊天室服务器和客户端代码示例

原文地址: http://www.cveoy.top/t/topic/f3qS 著作权归作者所有。请勿转载和采集!

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