netty笔记(一)--Demo

Netty是一个Java开源框架，用于传输数据。由server和client组成，封装了Java nio，支持TCP, UDP等协议。这里写了一Demo

EchoClientHandler.java

package chapter1;

import io.netty.buffer.ByteBuf;

import io.netty.buffer.Unpooled;

import io.netty.channel.ChannelHandler;

import io.netty.channel.ChannelHandlerContext;

import io.netty.channel.SimpleChannelInboundHandler;

import io.netty.util.CharsetUtil;

@ChannelHandler.Sharable

public class EchoClientHandler extends SimpleChannelInboundHandler<ByteBuf> {

    @Override

    public void channelActive(ChannelHandlerContext ctx) throws Exception {

        ctx.writeAndFlush(Unpooled.copiedBuffer("hello guanxianseng", CharsetUtil.UTF_8));

    }

    protected void messageReceived(ChannelHandlerContext ctx, ByteBuf msg) throws Exception {

        System.out.println("Client received:" + msg.toString(CharsetUtil.UTF_8));

        System.out.println(msg.toString());

    }

    @Override

    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {

        cause.printStackTrace();

        ctx.close();

    }

    @Override

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

        System.out.println("Client received:" + msg.toString());

    }

}

EchoServer.java

package chapter1;

import io.netty.bootstrap.ServerBootstrap;

import io.netty.channel.Channel;

import io.netty.channel.ChannelFuture;

import io.netty.channel.ChannelInitializer;

import io.netty.channel.EventLoopGroup;

import io.netty.channel.embedded.EmbeddedChannel;

import io.netty.channel.nio.NioEventLoopGroup;

import io.netty.channel.socket.SocketChannel;

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

import java.net.InetSocketAddress;

import java.util.concurrent.TimeUnit;

public class EchoServer {

    private  int port = 1234;

    public EchoServer(int port) {

        this.port = port;

    }

    public static void main(String[] args) throws Exception{

        int port = 1234;

        EchoServer echoServer = new EchoServer(port);

        schedulTask();

        echoServer.start();

    }

    public void start() throws Exception{

        final EchoServerHandler serverHandler = new EchoServerHandler();

        EventLoopGroup group = new NioEventLoopGroup();

        try{

            ServerBootstrap b = new ServerBootstrap();

            b.group(group)

                    .channel(NioServerSocketChannel.class)

                    .localAddress(new InetSocketAddress(port))

                    .childHandler(new ChannelInitializer<SocketChannel>() {

                        protected void initChannel(SocketChannel ch) throws Exception {

                            ch.pipeline().addLast(serverHandler);

                        }

                    });

            ChannelFuture channelFuture = b.bind().sync();

            System.out.println("sync test1");

            channelFuture.channel().closeFuture().sync();

            System.out.println("sync test2");

        } catch (Exception e){

        }finally {

            group.shutdownGracefully().sync();

            System.out.println("sync test3");

        }

    }

    public static void schedulTask(){

        System.out.println("before test");

        Channel ch = new EmbeddedChannel();

        ch.eventLoop().scheduleAtFixedRate(new Runnable() {

            public void run() {

                System.out.println("test");

            }

        }, 0, 5, TimeUnit.SECONDS);

    }

}

EchoClientHandler.java

package chapter1;

import io.netty.buffer.ByteBuf;

import io.netty.buffer.Unpooled;

import io.netty.channel.ChannelHandler;

import io.netty.channel.ChannelHandlerContext;

import io.netty.channel.SimpleChannelInboundHandler;

import io.netty.util.CharsetUtil;

@ChannelHandler.Sharable

public class EchoClientHandler extends SimpleChannelInboundHandler<ByteBuf> {

    @Override

    public void channelActive(ChannelHandlerContext ctx) throws Exception {

        ctx.writeAndFlush(Unpooled.copiedBuffer("hello guanxianseng", CharsetUtil.UTF_8));

    }

    protected void messageReceived(ChannelHandlerContext ctx, ByteBuf msg) throws Exception {

        System.out.println("Client received:" + msg.toString(CharsetUtil.UTF_8));

        System.out.println(msg.toString());

    }

    @Override

    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {

        cause.printStackTrace();

        ctx.close();

    }

    @Override

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

        System.out.println("Client received:" + msg.toString());

    }

}

EchoClient.java

package chapter1;

import io.netty.bootstrap.Bootstrap;

import io.netty.channel.ChannelFuture;

import io.netty.channel.ChannelInitializer;

import io.netty.channel.EventLoopGroup;

import io.netty.channel.nio.NioEventLoopGroup;

import io.netty.channel.socket.SocketChannel;

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

import java.net.InetSocketAddress;

public class EchoClient {

    private String host;

    private int port;

    public EchoClient(String host, int port) {

        this.host = host;

        this.port = port;

    }

    public static void main(String[] args) throws Exception {

        int port = 1234;

        String host = "127.0.0.1";

        EchoClient echoClient = new EchoClient(host, port);

        echoClient.start();

    }

    public void start() throws Exception{

        EventLoopGroup group = new NioEventLoopGroup();

        try{

            Bootstrap b = new Bootstrap();

            b.group(group)

                    .channel(NioSocketChannel.class)

                    .remoteAddress(new InetSocketAddress(host, port))

                    .handler(new ChannelInitializer<SocketChannel>() {

                        protected void initChannel(SocketChannel ch) throws Exception {

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

                        }

                    });

            ChannelFuture f = b.connect().sync();

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

        }catch (Exception e){

            e.printStackTrace();

        }finally {

            group.shutdownGracefully().sync();

        }

    }

}

netty如何实现各种回调，怎么发送、接收消息，还要看下源码

巴特西

netty笔记(一)--Demo

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