3、netty 之HelloWorld(netty学习笔记)

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HelloWorld 

客户端

package com.play.netty.timeserver.client;

import io.netty.bootstrap.Bootstrap;
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.NioSocketChannel;

/**
* Created by IntelliJ IDEA.
* User: GongQi
* Date: 2017/8/31
*/
public class TimeClient {

    public void connect(int port, String host) throws Exception {
        //建立客户端NIO线程组
        EventLoopGroup loopGroup = new NioEventLoopGroup();
        try {
            Bootstrap b = new Bootstrap();
            b.group(loopGroup)
                    .channel(NioSocketChannel.class)
                    .option(ChannelOption.TCP_NODELAY, true)
                    .handler(new ChannelInitializer<SocketChannel>() {
                        protected void initChannel(SocketChannel socketChannel) throws Exception {
                            socketChannel.pipeline().addLast(new TimeClientHandler());
                        }
                    });

            //发起异步连接
            ChannelFuture channelFuture=b.connect(host,port).sync();

            //等待客户端链路关闭
            channelFuture.channel().closeFuture().sync();

        } finally {
            loopGroup.shutdownGracefully();
        }

    }

    public static void main(String[] args) throws Exception {
            new TimeClient().connect(8080,"127.0.0.1");
    }
}

客户端处理器

package com.play.netty.timeserver.client;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerAdapter;
import io.netty.channel.ChannelHandlerContext;

/**
* Created by IntelliJ IDEA.
* User: GongQi
* Date: 2017/8/31
*/
public class TimeClientHandler extends ChannelHandlerAdapter {

    private final ByteBuf firstMessage;

    public TimeClientHandler() {
        byte[] bytes = "SHOW_TIME".getBytes();
        firstMessage = Unpooled.buffer(bytes.length);
        firstMessage.writeBytes(bytes);
    }

    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        ctx.writeAndFlush(firstMessage);
    }

    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        ByteBuf byteBuf = (ByteBuf) msg;
        byte[] bytes = new byte[byteBuf.readableBytes()];
        byteBuf.readBytes(bytes);
        String body = new String(bytes, "UTF-8");
        System.out.println("现在的时间是 :"+body);
        //

    }

    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        System.out.println("发生异常:"+cause.getMessage());
        ctx.close();
    }
}

服务端

package com.play.netty.timeserver.server;

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;

/**
* Created by IntelliJ IDEA.
* User: GongQi
* Date: 2017/8/31
*/
public class TimeServer {

    public void bind(Integer port) throws Exception {

        //配置服务端的NIO线程组
        EventLoopGroup bossGroup=new NioEventLoopGroup();
        EventLoopGroup workGroup=new NioEventLoopGroup();

        try{
            ServerBootstrap b=new ServerBootstrap();
            b.group(bossGroup,workGroup)
                    .channel(NioServerSocketChannel.class)
                    .option(ChannelOption.SO_BACKLOG,1024)
                    .childHandler(new ChildChannelHandler());

            //同步等待绑定端口完成
            //
            ChannelFuture channelFuture=b.bind(port).sync();

            //阻塞，只有当服务端链路关闭后才退出
            channelFuture.channel().closeFuture().sync();

        }finally {
            bossGroup.shutdownGracefully();
            workGroup.shutdownGracefully();
        }

    }

    private class ChildChannelHandler extends ChannelInitializer<SocketChannel>{
        protected void initChannel(SocketChannel socketChannel) throws Exception {
            socketChannel.pipeline().addLast(new TimeServerHandler());
        }
    }

    public static void main(String[] args) throws Exception {
        int port=8080;
        new TimeServer().bind(port);
    }

}

服务端处理器

package com.play.netty.timeserver.server;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerAdapter;
import io.netty.channel.ChannelHandlerContext;

import java.text.SimpleDateFormat;
import java.util.Date;

/**
* Created by IntelliJ IDEA.
* User: GongQi
* Date: 2017/8/31
*/
public class TimeServerHandler extends ChannelHandlerAdapter {

    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        //
        //
        ByteBuf buf = (ByteBuf) msg;
        byte[] bytes = new byte[buf.readableBytes()];
        buf.readBytes(bytes);
        String databody = new String(bytes, "UTF-8");
        System.out.println("the client cmd id " + databody);
        //
        SimpleDateFormat format = new SimpleDateFormat("yyyyMMdd hh:mm:ss");

        String currtime = "SHOW_TIME".equals(databody) ? format.format(new Date()) : "BAD_CMD";
        ByteBuf resp = Unpooled.copiedBuffer(currtime.getBytes());
        ctx.write(resp);
    }

    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
        ctx.flush();
    }

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