Netty入门示例

服务端

package com._656463.netty.ch01;

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

public class HelloServer {
    public static void main(String[] args) {
        //创建Boss和work的NioEventLoopGroup，两个都算无限循环
        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
        EventLoopGroup workGroup = new NioEventLoopGroup();

        try {
            //创建服务端启动对象，配置参数
            ServerBootstrap bootstrap = new ServerBootstrap();

            bootstrap
                    //设置线程组
                    .group(bossGroup, workGroup)
                    //使用NioServerSocketChannel作为服务端的通道实现
                    .channel(NioServerSocketChannel.class)
                    //设置线程队列的连接个数
                    .option(ChannelOption.SO_BACKLOG, 128)
                    //设置保存活动的连接状态
                    .childOption(ChannelOption.SO_KEEPALIVE, true)
                    //创建一个通道初始对象
                    .childHandler(new ChannelInitializer<SocketChannel>() {
                        //给pipeline设置处理器
                        @Override
                        protected void initChannel(SocketChannel ch) throws Exception {
                            ch.pipeline().addLast(new HelloServerHandler());
                        }
                    });

            ChannelFuture future = bootstrap.bind(8080).sync();
            future.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            bossGroup.shutdownGracefully();
            workGroup.shutdownGracefully();
        }
    }
}

服务端处理器

package com_656463.netty.ch01;

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.util.concurrent.TimeUnit;

/**
 * 自定义Handler
 */
public class HelloServerHandler extends ChannelInboundHandlerAdapter {
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        System.out.println("server channelRead..");
        ByteBuf buf = (ByteBuf) msg;
        System.out.println("客户端【" + ctx.channel().remoteAddress() + "】发送消息 :" + buf.toString(CharsetUtil.UTF_8));
    }

    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
        ctx.writeAndFlush(Unpooled.copiedBuffer("hello client", CharsetUtil.UTF_8));
    }

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

客户端

package com_656463.netty.ch01;

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 HelloClient {
    public static void main(String[] args) {
        NioEventLoopGroup eventExecutors = new NioEventLoopGroup();
        Bootstrap bootstrap = new Bootstrap();

        try {
            bootstrap.group(eventExecutors)
                    .channel(NioSocketChannel.class)
                    .handler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        protected void initChannel(SocketChannel ch) throws Exception {
                            ch.pipeline().addLast(new HelloClientHandler());
                        }
                    });

            ChannelFuture channelFuture = bootstrap.connect("127.0.0.1", 8080).sync();
            channelFuture.channel().closeFuture().sync();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            eventExecutors.shutdownGracefully();
        }
    }
}

客户端处理类

package com_656463.netty.ch01;

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;

/**
 * 自定义Handler
 */
public class HelloClientHandler extends ChannelInboundHandlerAdapter {

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        ctx.writeAndFlush(Unpooled.copiedBuffer("hello server",CharsetUtil.UTF_8));
    }

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        System.out.println("server channelRead..");
        ByteBuf buf = (ByteBuf) msg;
        System.out.println("服务端【" + ctx.channel().remoteAddress() + "】回复消息 :" + buf.toString(CharsetUtil.UTF_8));
    }

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