Netty简单聊天室

1、创建maven项目，在pom.xml中引入netty的jar包

<project xmlns="http://maven.apache.org/POM/4.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.cppdy</groupId>
    <artifactId>NettyDemo</artifactId>
    <version>0.0.1-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>io.netty</groupId>
            <artifactId>netty-all</artifactId>
            <version>4.1.32.Final</version>
        </dependency>
    </dependencies>

</project>

2、创建server处理程序类

package com.cppdy.server;

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

public class ChatServerHandler extends SimpleChannelInboundHandler<String>{

    @Override
    protected void channelRead0(ChannelHandlerContext arg0, String msg) throws Exception {

        System.out.println(msg);
    }

}

3、创建server初始化类

package com.cppdy.server;

import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;

public class ChatServerInit extends ChannelInitializer<SocketChannel>{

    @Override
    protected void initChannel(SocketChannel sc) throws Exception {

        ChannelPipeline pipeline = sc.pipeline();
        pipeline.addLast("decoder",new StringDecoder());
        pipeline.addLast("encoder",new StringEncoder());
        pipeline.addLast("handler",new ChatServerHandler());
    }

}

4、创建server启动类

package com.cppdy.server;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelOption;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioServerSocketChannel;

public class ChatServer {

    public static void main(String[] args) {
        NioEventLoopGroup boss = new NioEventLoopGroup();
        NioEventLoopGroup worker = new NioEventLoopGroup();

        try {
            ServerBootstrap b = new ServerBootstrap();
            b.group(boss, worker).channel(NioServerSocketChannel.class).childHandler(new ChatServerInit())
                    .option(ChannelOption.SO_BACKLOG, 128).childOption(ChannelOption.SO_KEEPALIVE, true);

            System.out.println("服务端启动啦……");

            ChannelFuture sync = b.bind(8080).sync();
            sync.channel().closeFuture().sync();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            boss.shutdownGracefully();
            worker.shutdownGracefully();
        }
    }
}

5、创建client处理程序类

package com.cppdy.client;

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

public class ChatClientHandler extends SimpleChannelInboundHandler<String> {

    @Override
    protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {

        System.out.println(msg);
    }

}

6、创建client初始化类

package com.cppdy.client;

import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;

public class ChatClientInit extends ChannelInitializer<SocketChannel> {

    @Override
    protected void initChannel(SocketChannel sc) throws Exception {

        ChannelPipeline pipeline = sc.pipeline();
        pipeline.addLast("decoder", new StringDecoder());
        pipeline.addLast("encoder", new StringEncoder());
        pipeline.addLast("handler", new ChatClientHandler());

    }

}

7、创建client启动类

package com.cppdy.client;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.InetSocketAddress;

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

public class ChatClient {

    public static void main(String[] args) {
        NioEventLoopGroup group = new NioEventLoopGroup();
        try {
            Bootstrap bootstrap = new Bootstrap().group(group).channel(NioSocketChannel.class)
                    .handler(new ChatClientInit());
            Channel channel = bootstrap.connect(new InetSocketAddress("127.0.0.1", 8080)).sync().channel();
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
            while (true) {
                channel.writeAndFlush(bufferedReader.readLine() + "\r\n");
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            group.shutdownGracefully();
        }
    }
}

8、先启动ChatServer类，再启动ChatClient类，就可以模拟发送消息功能。