package com.zhaowb.netty.ch5_1;

import io.netty.bootstrap.ServerBootstrap;

import io.netty.buffer.ByteBuf;

import io.netty.buffer.Unpooled;

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;

import io.netty.handler.codec.DelimiterBasedFrameDecoder;

import io.netty.handler.codec.string.StringDecoder;

import io.netty.handler.logging.LogLevel;

import io.netty.handler.logging.LoggingHandler;

public class EchoServer {

    public void bind(int port) throws Exception {

        // 配置 服务端的 NIO 线程组

        EventLoopGroup bossGroup = new NioEventLoopGroup();

        EventLoopGroup workerGroup = new NioEventLoopGroup();

        try {

            ServerBootstrap b = new ServerBootstrap();

            b.group(bossGroup, workerGroup)

                    .channel(NioServerSocketChannel.class)

                    .option(ChannelOption.SO_BACKLOG, 1024)

                    .handler(new LoggingHandler(LogLevel.INFO))

                    .childHandler(new ChannelInitializer<SocketChannel>() {

                        @Override

                        protected void initChannel(SocketChannel ch) throws Exception {

                            ByteBuf delimiter = Unpooled.copiedBuffer("$_".getBytes());// 创建分隔符对象 ByteBuf 使用 $_ 作为分隔符。

                            // 第一个参数为单条消息的最大长度，当达到该长度后仍然没有查找到分隔符，就抛出 TooLongFrameException 异常

                            // 防止由于异常码流缺失分隔符导致的内存溢出，这是 netty 解码器的可靠性保护;第二个参数是分隔符缓冲对象。

                            ch.pipeline().addLast(new DelimiterBasedFrameDecoder(1024, delimiter));

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

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

                        }

                    });

            // 绑定端口，同步等待成功。

            ChannelFuture f = b.bind(port).sync();

            // 等待服务端监听端口关闭。

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

        } catch (Exception e) {

            // 退出，释放线程池资源

            bossGroup.shutdownGracefully();

            workerGroup.shutdownGracefully();

        }

    }

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

        int port = 8080;

        if (args != null && args.length > 0) {

            try {

                port = Integer.valueOf(args[0]);

            } catch (NumberFormatException e) {

            }

        }

        new EchoServer().bind(port);

    }

}

package com.zhaowb.netty.ch5_1;

import io.netty.buffer.ByteBuf;

import io.netty.buffer.Unpooled;

import io.netty.channel.ChannelHandlerAdapter;

import io.netty.channel.ChannelHandlerContext;

public class EchoServerHandler extends ChannelHandlerAdapter {

    int counter = 0;

    @Override

    public void channelActive(ChannelHandlerContext ctx) throws Exception {

        System.out.println("链接成功！");

    }

    @Override

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

        // 当读取信息时，先经过 DelimiterBasedFrameDecoder 去掉结束分隔符，然后再使用 StringDecoder 将 ByteBuf 解码成字符串/

        // 然后 EchoServerHandler 收到的数据就是解码后的字符串对象

        String body = (String) msg;

        System.out.println("This is " + ++counter + " times receive client : [" + body + "]");

        body += "$_"; // 由于 设置 DelimiterBasedFrameDecoder 过滤掉了分隔符，返回给客户端时需要在消息的尾部拼接 "$_"

        ByteBuf echo = Unpooled.copiedBuffer(body.getBytes());

        ctx.writeAndFlush(echo);

    }

    @Override

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

        cause.printStackTrace();

        ctx.close();// 发生异常，关闭链路

    }

}

package com.zhaowb.netty.ch5_1;

import io.netty.bootstrap.Bootstrap;

import io.netty.buffer.ByteBuf;

import io.netty.buffer.Unpooled;

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;

import io.netty.handler.codec.DelimiterBasedFrameDecoder;

import io.netty.handler.codec.string.StringDecoder;

import io.netty.handler.logging.LogLevel;

import io.netty.handler.logging.LoggingHandler;

public class EchoClient {

    public void connect(int port, String host) throws Exception {

        //配置客户端 NIO 线程组

        EventLoopGroup group = new NioEventLoopGroup();

        try {

            Bootstrap b = new Bootstrap();

            b.group(group).channel(NioSocketChannel.class)

                    .option(ChannelOption.TCP_NODELAY, true)

                    .handler(new ChannelInitializer<SocketChannel>() {

                        @Override

                        protected void initChannel(SocketChannel ch) throws Exception {

                            ByteBuf delimiter = Unpooled.copiedBuffer("$_".getBytes());// 创建分隔符对象 ByteBuf 使用 $_ 作为分隔符。

                            ch.pipeline().addLast(new DelimiterBasedFrameDecoder(1024, delimiter));

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

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

                        }

                    });

            // 发起异步连接操作

            ChannelFuture f = b.connect(host, port).sync();

            // 等待客户端链路关闭

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

        } finally {

            // 释放 NIO 线程组

            group.shutdownGracefully();

        }

    }

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

        int port = 8080;

        if (args != null && args.length > 0) {

            try {

                port = Integer.valueOf(args[0]);

            } catch (NumberFormatException e) {

            }

        }

        new EchoClient().connect(port, "127.0.0.1");

    }

}

package com.zhaowb.netty.ch5_1;

import io.netty.buffer.Unpooled;

import io.netty.channel.ChannelHandlerAdapter;

import io.netty.channel.ChannelHandlerContext;

public class EchoClientHandler extends ChannelHandlerAdapter {

    private int counter;

    static final String ECHO_REQ = "hello.$_";

    public EchoClientHandler() {

    }

    @Override

    public void channelActive(ChannelHandlerContext ctx) throws Exception {

        System.out.println("链接成功！");

        for (int i = 0; i < 10; i++) {

            ctx.writeAndFlush(Unpooled.copiedBuffer(ECHO_REQ.getBytes()));

        }

    }

    @Override

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

        System.out.println("This is " + ++counter + "times receive server : [" + msg.toString() + "]");

    }

    @Override

    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {

        ctx.flush();

    }

    @Override

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

        cause.printStackTrace();

        ctx.close();

    }

}