Netty4.X 学习（一）

Server:

import io.netty.buffer.ByteBuf;

import io.netty.channel.ChannelHandlerContext;

import io.netty.channel.ChannelInboundHandlerAdapter;

import io.netty.util.CharsetUtil;

import io.netty.util.ReferenceCountUtil;



import com.netty.utils.*;



public class HelloServerHandler extends ChannelInboundHandlerAdapter {

    @Override

    public void channelActive(ChannelHandlerContext ctx) throws Exception {

        Log.logInfo(">>>>>> I'm server.");

        // System.out.println(">>>>>> I'm server.");

        String msg = "Hello world\n";

        ByteBuf encoded = ctx.alloc().buffer(msg.length());

        encoded.writeBytes(msg.getBytes());

        ctx.write(encoded);

        ctx.flush();

    }



    @Override

    public void channelRead(ChannelHandlerContext ctx, Object msg)

            throws Exception {

        //Log.logInfo("server receive message:" + msg);

        // System.out.println("服务器收到的消息:" + msg);

        ByteBuf in = (ByteBuf) msg;

        try {

            if (in.isReadable()) { // (1)

                String str = in.toString(CharsetUtil.US_ASCII);

                Log.logInfo("server receive message:" + str);

            }

        } finally {

            ReferenceCountUtil.release(msg); // (2)

        }



    }

}

package com.netty.example.PrintHello;



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 HelloWorldServer {

    public static void main(String[] args) {

        //EventLoop 代替原来的 ChannelFactory

        EventLoopGroup bossGroup = new NioEventLoopGroup();

        EventLoopGroup workerGroup = new NioEventLoopGroup();

        try {

            ServerBootstrap serverBootstrap = new ServerBootstrap();

            // server端采用简洁的连写方式，client端才用分段普通写法。

            serverBootstrap.group(bossGroup, workerGroup)

                    .channel(NioServerSocketChannel.class)

                    .childHandler(new ChannelInitializer<SocketChannel>() {

                        @Override

                        public void initChannel(SocketChannel ch)

                                throws Exception {

                            ch.pipeline().addLast(new HelloServerHandler());

                        }

                    }).option(ChannelOption.SO_KEEPALIVE, true);



            ChannelFuture f = serverBootstrap.bind(8000).sync();

            f.channel().closeFuture().sync();

            System.out.println("TCP服务器已启动");

        } catch (InterruptedException e) {

        } finally {

            workerGroup.shutdownGracefully();

            bossGroup.shutdownGracefully();

        }

    }

}

运行后可以在终端直接通过telnet命令连接：

telnet localhost 8000

 

client：

package com.netty.example.PrintHello;

import io.netty.buffer.ByteBuf;

import io.netty.channel.ChannelHandlerContext;

import io.netty.channel.ChannelInboundHandlerAdapter;

import io.netty.util.ReferenceCountUtil;



public class HelloClientHandler  extends ChannelInboundHandlerAdapter{

    @Override

    public void channelActive(ChannelHandlerContext ctx) throws Exception {

        System.out.println(">>>>> I'm client.");

//        ctx.write("Hello world!");

//        ctx.flush();

        String msg = "Are you ok?";  

        ByteBuf encoded = ctx.alloc().buffer(msg.length());  

        encoded.writeBytes(msg.getBytes());  

        ctx.write(encoded);  

        ctx.flush(); 

    }

    

    @Override

    public void channelRead(ChannelHandlerContext ctx, Object msg)  throws Exception{

        ByteBuf in = (ByteBuf) msg;

        try {

            while (in.isReadable()) { // (1)

                System.out.println("client收到服务器的消息:" + msg);

                System.out.print((char) in.readByte());

                System.out.flush();

            }

        } finally {

            ReferenceCountUtil.release(msg); // (2)

        }

    }

}

package com.netty.example.PrintHello;



import java.net.InetSocketAddress;



import io.netty.bootstrap.Bootstrap;

import io.netty.bootstrap.ServerBootstrap;

import io.netty.channel.ChannelFuture;

import io.netty.channel.ChannelHandlerContext;

import io.netty.channel.ChannelInboundHandlerAdapter;

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;

import io.netty.channel.socket.nio.NioSocketChannel;



public class HelloWorldClient {

    public static void main(String[] args) {

        // Client服务启动器 3.x的ClientBootstrap 改为Bootstrap，且构造函数变化很大，这里用无参构造。

        Bootstrap bootstrap = new Bootstrap();

        // 指定channel类型

        bootstrap.channel(NioSocketChannel.class);

        // 指定Handler

        bootstrap.handler(new HelloClientHandler());

        // 指定EventLoopGroup

        bootstrap.group(new NioEventLoopGroup());

        // 连接到本地的8000端口的服务端

        bootstrap.connect(new InetSocketAddress("127.0.0.1", 8000));

    }

}