（二）Netty基础操作案例

Netty网络聊天室：

ChatClient 网络聊天室客户端

package com.bestqiang.netty.chat;

import io.netty.bootstrap.Bootstrap;
import io.netty.channel.*;
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.util.Scanner;

//聊天程序客户端
public class ChatClient {
    private final String host; //服务器端IP地址
    private final int port;  //服务器端端口号

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

    public void run(){
        EventLoopGroup group = new NioEventLoopGroup();
        try {
            Bootstrap bootstrap = new Bootstrap()
                    .group(group)
                    .channel(NioSocketChannel.class)
                    .handler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        public void initChannel(SocketChannel ch){
                            ChannelPipeline pipeline=ch.pipeline();
                            //往pipeline链中添加一个解码器
                            pipeline.addLast("decoder",new StringDecoder());
                            //往pipeline链中添加一个编码器
                            pipeline.addLast("encoder",new StringEncoder());
                            //往pipeline链中添加自定义的handler(业务处理类)
                            pipeline.addLast(new ChatClientHandler());
                        }
                    });

            ChannelFuture cf=bootstrap.connect(host,port).sync();
            Channel channel=cf.channel();
            System.out.println("------"+channel.localAddress().toString().substring(1)+"------");
            Scanner scanner=new Scanner(System.in);
            while (scanner.hasNextLine()){
                String msg=scanner.nextLine();
                channel.writeAndFlush(msg+"\r\n");
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            group.shutdownGracefully();
        }
    }

    public static void main(String[] args) throws Exception {
        new ChatClient("127.0.0.1",9999).run();
    }
}

网络聊天室服务器端：

package com.bestqiang.netty.chat;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.*;
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;

//聊天程序服务器端
public class ChatServer {

    private int port; //服务器端端口号

    public ChatServer(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)
                    .option(ChannelOption.SO_BACKLOG, 128)
                    .childOption(ChannelOption.SO_KEEPALIVE, true)
                    .childHandler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        public void initChannel(SocketChannel ch) {
                            ChannelPipeline pipeline=ch.pipeline();
                            //往pipeline链中添加一个解码器
                            pipeline.addLast("decoder",new StringDecoder());
                            //往pipeline链中添加一个编码器
                            pipeline.addLast("encoder",new StringEncoder());
                            //往pipeline链中添加自定义的handler(业务处理类)
                            pipeline.addLast(new ChatServerHandler());
        }
    });
            System.out.println("Netty Chat Server启动......");
    ChannelFuture f = b.bind(port).sync();
            f.channel().closeFuture().sync();
        } finally {
            workerGroup.shutdownGracefully();
            bossGroup.shutdownGracefully();
            System.out.println("Netty Chat Server关闭......");
        }
    }

    public static void main(String[] args) throws Exception {
        new ChatServer(9999).run();
    }
}

客户端业务处理类：

package com.bestqiang.netty.chat;

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

//自定义一个客户端业务处理类
public class ChatClientHandler extends SimpleChannelInboundHandler<String> {
    @Override
    protected void channelRead0(ChannelHandlerContext ctx, String s) throws Exception {
        System.out.println(s.trim());
    }
}

服务器端业务处理类：

package com.bestqiang.netty.chat;

import io.netty.channel.Channel;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.channel.group.ChannelGroup;
import io.netty.channel.group.DefaultChannelGroup;
import io.netty.util.concurrent.GlobalEventExecutor;

import java.util.ArrayList;
import java.util.List;

//自定义一个服务器端业务处理类
public class ChatServerHandler extends SimpleChannelInboundHandler<String> {

    public static List<Channel> channels = new ArrayList<>();

    @Override  //通道就绪
    public void channelActive(ChannelHandlerContext ctx)  {
        Channel inChannel=ctx.channel();
        channels.add(inChannel);
        System.out.println("[Server]:"+inChannel.remoteAddress().toString().substring(1)+"上线");
    }
    @Override  //通道未就绪
    public void channelInactive(ChannelHandlerContext ctx)  {
        Channel inChannel=ctx.channel();
        channels.remove(inChannel);
        System.out.println("[Server]:"+inChannel.remoteAddress().toString().substring(1)+"离线");
    }
    @Override  //读取数据
    protected void channelRead0(ChannelHandlerContext ctx, String s)  {
        Channel inChannel=ctx.channel();
        for(Channel channel:channels){
            if(channel!=inChannel){
                channel.writeAndFlush("["+inChannel.remoteAddress().toString().substring(1)+"]"+"说："+s+"\n");
            }
        }
    }

}