netty的简单使用

　　关于基本的使用，算是小入门

一：基本使用

1.服务端

package com.jun.netty.base;

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

public class NettyServer {
    public static void main(String[] args) {
        NioEventLoopGroup bossGroup = new NioEventLoopGroup(2);
        NioEventLoopGroup workerGroup = new NioEventLoopGroup(10);
        try {
            ServerBootstrap serverBootstrap = new ServerBootstrap();
            serverBootstrap.group(bossGroup, workerGroup)
                    .channel(NioServerSocketChannel.class)
                    .option(ChannelOption.SO_BACKLOG, 1024)
                    .childHandler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        protected void initChannel(SocketChannel socketChannel) throws Exception {
                            socketChannel.pipeline().addLast(new NettyServerHandler());
                        }
                    });
            System.out.println("netty server start");
            ChannelFuture future = serverBootstrap.bind(9000).sync();
            future.channel().closeFuture().sync();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }
}

　　其中，处理器

package com.jun.netty.base;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandler;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.util.CharsetUtil;
import io.netty.util.concurrent.EventExecutorGroup;

public class NettyServerHandler extends ChannelInboundHandlerAdapter {
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        System.out.println("客户端已经链接");
    }


    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        ByteBuf buf = (ByteBuf) msg;
        System.out.println("接收到客户端的数据是=" + buf.toString(CharsetUtil.UTF_8));
    }

    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
        ByteBuf byteBuf = Unpooled.copiedBuffer("hello client".getBytes(CharsetUtil.UTF_8));
        ctx.writeAndFlush(byteBuf);
        super.channelReadComplete(ctx);
    }
}

 

2.客户端

package com.jun.netty.base;

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

public class NettyClient {
    public static void main(String[] args) {
        NioEventLoopGroup group = new NioEventLoopGroup();
        try {
            Bootstrap bootstrap = new Bootstrap();
            bootstrap.group(group)
                    .channel(NioSocketChannel.class)
                    .handler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        protected void initChannel(SocketChannel socketChannel) throws Exception {
                            socketChannel.pipeline().addLast(new NettyClientHandler());
                        }
                    });
            System.out.println("netty client start");
            ChannelFuture future = bootstrap.connect("127.0.0.1", 9000).sync();
            future.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        } finally {
            group.shutdownGracefully();
        }
    }
}

　　其中，处理器

package com.jun.netty.base;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.util.CharsetUtil;

import java.nio.ByteBuffer;

public class NettyClientHandler extends ChannelInboundHandlerAdapter {
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        ByteBuf byteBuf = Unpooled.copiedBuffer("hello server".getBytes(CharsetUtil.UTF_8));
        ctx.writeAndFlush(byteBuf);
    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        ByteBuf byteBuf = (ByteBuf) msg;
        System.out.println("接收到的服务端的小写" + byteBuf.toString(CharsetUtil.UTF_8));
    }
}

 

二：聊天室

1.客户端

package com.jun.netty.chat;

import io.netty.bootstrap.Bootstrap;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
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;

public class ChatClient {
    public static void main(String[] args) throws InterruptedException {
        NioEventLoopGroup group = new NioEventLoopGroup();
        try {
            Bootstrap bootstrap = new Bootstrap();
            bootstrap
                    .group(group)
                    .channel(NioSocketChannel.class)
                    .handler(new ChannelInitializer<SocketChannel>() {
                @Override
                protected void initChannel(SocketChannel socketChannel) throws Exception {
                    ChannelPipeline pipeline = socketChannel.pipeline();
                    pipeline.addLast("decoder", new StringDecoder());
                    pipeline.addLast("encoder", new StringEncoder());
                    pipeline.addLast(new ChatClientHandler());
                }
            });
            ChannelFuture future = bootstrap.connect("127.0.0.1", 9000).sync();
            Channel channel = future.channel();
            System.out.println("========" + channel.localAddress() + "========");
            // 客户端输入信息
            Scanner scanner = new Scanner(System.in);
            while (scanner.hasNext()) {
                String msg = scanner.nextLine();
                channel.writeAndFlush(msg);
            }
        } finally {
            group.shutdownGracefully();
        }
    }
}

　　对应处理器

package com.jun.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;

public class ChatClientHandler extends SimpleChannelInboundHandler<String> {
    @Override
    protected void channelRead0(ChannelHandlerContext channelHandlerContext, String s) throws Exception {
        System.out.println(s.trim());
    }


}

 

2.服务端

package com.jun.netty.chat;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.ChannelPipeline;
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;

/**
 * 聊天室的服务端
 */
public class ChatServer {
    public static void main(String[] args) {
        NioEventLoopGroup boosGroup = new NioEventLoopGroup(1);
        NioEventLoopGroup workerGroup = new NioEventLoopGroup(8);
        try {
            ServerBootstrap serverBootstrap = new ServerBootstrap();
            serverBootstrap
                    .group(boosGroup, workerGroup)
                    .channel(NioServerSocketChannel.class)
                    .option(ChannelOption.SO_BACKLOG, 1024)
                    .childHandler(new ChannelInitializer<SocketChannel>() {
                @Override
                protected void initChannel(SocketChannel socketChannel) throws Exception {
                    ChannelPipeline pipeline = socketChannel.pipeline();
                    pipeline.addLast("decoder", new StringDecoder());
                    pipeline.addLast("encoder", new StringEncoder());
                    pipeline.addLast(new ChatServerHandler());
                }
            });
            System.out.println("聊天室server启动");
            ChannelFuture future = serverBootstrap.bind(9000).sync();
            future.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        } finally {
            boosGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }
}

　　对应处理器

package com.jun.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;

public class ChatServerHandler extends SimpleChannelInboundHandler<String> {
    private static ChannelGroup channelGroup = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        Channel channel = ctx.channel();
        channelGroup.writeAndFlush("[客户端]"+channel.remoteAddress() + "上线了");
        channelGroup.add(channel);
        System.out.println(channel.remoteAddress() + "上线了");
    }

    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        Channel channel = ctx.channel();
        channelGroup.writeAndFlush("[客户端]"+channel.remoteAddress() + "下线了");
        System.out.println(channel.remoteAddress() + "下线了");
    }

    @Override
    protected void channelRead0(ChannelHandlerContext ctx, String s) throws Exception {
        Channel channel = ctx.channel();
        channelGroup.forEach(ch -> {
            if(channel != ch){
                ch.writeAndFlush("[客户端]" + channel.remoteAddress() + "发送了信息" + s);
            }else {
                ch.writeAndFlush("[自己]发送了信息" + s);
            }
        });
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
        //关闭通道
        ctx.close();
    }
}

 

3.效果

　　服务端：

　　

 

 

 

　　客户端1：

　　

 

 

　　客户端2