Netty网络编程实战之开发聊天室功能

package com.guor.demo.netty.chat;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.NIO.NioEventLoopGroup;
import io.netty.channel.Socket.nio.NiOServerSocketChannel;

public class MyNettyServerTest {
    public static void main(String[] args) throws InterruptedException {
        
        EventLoopGroup serverGroup = new NioEventLoopGroup();
        EventLoopGroup clientGroup = new NioEventLoopGroup();
        try {
            // 服务端启动时的初始化操作
            ServerBootstrap serverBootstrap = new ServerBootstrap();
            // 1、将serverGroup和clientGroup注册到服务端的Channel上；
            // 2、注册一个服务端的初始化器MyNettyServerInitializer；
            // 3、该初始化器中的initChannel()方法会在连接被注册到Channel后立刻执行；
            // 5、最后将端口号绑定到8080；
            ChannelFuture channelFuture = serverBootstrap.group(serverGroup, clientGroup)
                    .channel(NioServerSocketChannel.class)
                    .childHandler(new MyNettyServerInitializer()).bind(8080).sync();
            channelFuture.channel().closeFuture().sync();
        }catch (Exception e){
            System.out.println(e);
        }finally {
            serverGroup.shutdownGracefully();
            clientGroup.shutdownGracefully();
        }
    }
}

package com.guor.demo.netty.chat;

import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.LengthFieldBasedFrameDecoder;
import io.netty.handler.codec.LengthFieldPrepender;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;
import io.netty.util.CharsetUtil;


public class MyNettyServerInitializer extends ChannelInitializer<SocketChannel> {

    // 连接被注册到Channel后，立刻执行此方法
    @Override
    protected void initChannel(SocketChannel socketChannel) throws Exception {
        ChannelPipeline pipeline = socketChannel.pipeline();
        
        pipeline.addLast("LengthFieldBasedFrameDecoder",new LengthFieldBasedFrameDecoder(Integer.MAX_VALUE,0,8,0,8));
        // 将上条语句的length加入传递的数据中心
        pipeline.addLast("LengthFieldPrepender",new LengthFieldPrepender(8));
        // 传递字符串的编码解码器
        pipeline.addLast("StringDecoder",new StringDecoder(CharsetUtil.UTF_8));
        pipeline.addLast("StringEecoder",new StringEncoder(CharsetUtil.UTF_8));
        // 增加自定义处理器MyNettyServerHandler，用于实际处理请求，并给出响应
        pipeline.addLast("MyNettyServerHandler",new MyNettyServerHandler());
    }
}

package com.guor.demo.netty.chat;

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

import java.util.Scanner;


public class MyNettyServerHandler extends SimpleChannelInboundHandler<String> {

    @Override
    protected void channelRead0(ChannelHandlerContext ctx, String receiveMsg) throws Exception {
        // 通过ctx获取客户端的IP和端口号，并打印出客户端发来的消息
        System.out.println("服务端接收的请求来自："+ctx.channel().remoteAddress()+",消息内容："+receiveMsg);

        System.out.println("请向客户端发送一条消息：");
        String sendMsg = new Scanner(System.in).nextLine();
        ctx.channel().writeAndFlush(sendMsg);
    }
}

package com.guor.demo.netty.chat;

import io.netty.bootstrap.Bootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioSocketChannel;


public class MyNettyClientTest {
    public static void main(String[] args) {
        
        EventLoopGroup eventLoopGroup = new NioEventLoopGroup();
        try {
            // 客户端启动时的初始化操作
            Bootstrap bootstrap = new Bootstrap();
            bootstrap.group(eventLoopGroup)
                    .channel(NioSocketChannel.class)
                    .handler(new MyNettyClientInitializer());
            ChannelFuture channelFuture = bootstrap.connect("127.0.0.1", 8080).sync();
            channelFuture.channel().closeFuture().sync();
        }catch (Exception e){
            System.out.println(e);
        }finally {
            eventLoopGroup.shutdownGracefully();
        }
    }
}

package com.guor.demo.netty.chat;

import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.LengthFieldBasedFrameDecoder;
import io.netty.handler.codec.LengthFieldPrepender;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;
import io.netty.util.CharsetUtil;


public class MyNettyClientInitializer extends ChannelInitializer<SocketChannel> {

    // 连接被注册后，立即执行此方法
    @Override
    protected void initChannel(SocketChannel socketChannel) throws Exception {
        ChannelPipeline pipeline = socketChannel.pipeline();
        
        pipeline.addLast("LengthFieldBasedFrameDecoder",new LengthFieldBasedFrameDecoder(Integer.MAX_VALUE,0,8,0,8));
        // 将上条语句的length加入传递的数据中心
        pipeline.addLast("LengthFieldPrepender",new LengthFieldPrepender(8));
        // 传递字符串的编码解码器
        pipeline.addLast("StringDecoder",new StringDecoder(CharsetUtil.UTF_8));
        pipeline.addLast("StringEecoder",new StringEncoder(CharsetUtil.UTF_8));
        // 增加自定义处理器MyNettyClientHandler
        pipeline.addLast("MyNettyClientHandler",new MyNettyClientHandler());
    }
}

package com.guor.demo.netty.chat;

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

import java.util.Scanner;


public class MyNettyClientHandler extends SimpleChannelInboundHandler<String> {

    @Override
    protected void channelRead0(ChannelHandlerContext ctx, String receiveMsg) throws Exception {
        System.out.println("客户端接收的请求来自："+ctx.channel().remoteAddress()+",消息内容："+receiveMsg);

        System.out.println("请向服务端发送一条消息：");

        String sendMsg = new Scanner(System.in).nextLine();

        ctx.channel().writeAndFlush(sendMsg);
    }

    public void channelActive(ChannelHandlerContext ctx) throws Exception{
        ctx.writeAndFlush("第一条消息...");
    }
}