第一个Netty程序

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<span style="font-family: Arial, Helvetica, sans-serif; background-color: rgb(255, 255, 255);">去官网下载Netty包，导入jar文件即可</span>

客服端代码

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;public class TimeClient {    public void connect(int port, String host) throws Exception {        // 创建客户端NIO线程组        EventLoopGroup group = new NioEventLoopGroup();        try {            Bootstrap b = new Bootstrap();//启动NIO服务的辅助启动类，为了降低服务端的开发复杂度            b.group(group).channel(NioSocketChannel.class).option(ChannelOption.TCP_NODELAY, true)                    .handler(new ChannelInitializer<SocketChannel>() {                        //创建NioSocketChannel成功之后，初始化的时候将它的SocketChannel设置到ChannelPipeline中用于处理网络IO事件。                        @Override                        public void initChannel(SocketChannel ch) throws Exception {                            ch.pipeline().addLast(new TimeClientHandler());                        }                    });            // 发起异步连接操作            ChannelFuture f = b.connect(host, port).sync();            // 阻塞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;        new TimeClient().connect(port, "127.0.0.1");    }}

</pre><pre name="code" class="java">

import io.netty.buffer.ByteBuf;import io.netty.buffer.Unpooled;import io.netty.channel.ChannelHandlerAdapter;import io.netty.channel.ChannelHandlerContext;import java.util.logging.Logger;public class TimeClientHandler extends ChannelHandlerAdapter {    private static final Logger logger = Logger.getLogger(TimeClientHandler.class.getName());    private final ByteBuf firstMessage;    //初始化要发送的数据    public TimeClientHandler() {        byte[] req = "当前时间是：".getBytes();        firstMessage = Unpooled.buffer(req.length);        firstMessage.writeBytes(req);    }    @Override    public void channelActive(ChannelHandlerContext ctx) {        ctx.writeAndFlush(firstMessage);  //发送信息给服务器    }    @Override    public void channelRead(ChannelHandlerContext ctx, Object msg)            throws Exception {        ByteBuf buf = (ByteBuf) msg;        byte[] req = new byte[buf.readableBytes()];//获得缓冲区可读的字节数组，用于创建新的字节数组        buf.readBytes(req);//将缓冲区的字节数组复制到新创建的字节数组中        String body = new String(req, "UTF-8");        System.out.println(body);    }    @Override    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {        System.out.print("异常？");        // 释放资源        logger.warning("Unexpected exception from downstream : "                + cause.getMessage());        ctx.close();    }}

服务端代码

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 TimeServer {    public void bind(int port) throws Exception {        // 配置服务端的NIO线程组        EventLoopGroup bossGroup = new NioEventLoopGroup();//接受客服的链接        EventLoopGroup workerGroup = new NioEventLoopGroup();//进行SocketChannel的读写操作        try {            ServerBootstrap b = new ServerBootstrap();//启动NIO服务的辅助启动类，为了降低服务端的开发复杂度            /* 将两个NIO加入到ServerBootstrap中，接着创建Channel为NIOServerSocketChannel,相当于ServerSocketChannel类。            配置NIOServerSocketChannel的TCP参数将块大小设置成1024.最后绑定IO事件的处理类ChildChannelHander,主要处理网络IO事件对信息进行编解码等。*/            b.group(bossGroup, workerGroup).channel(NioServerSocketChannel.class).option(ChannelOption.SO_BACKLOG, 1024).childHandler(new ChildChannelHandler());            // 绑定端口，同步等待成功            ChannelFuture f = b.bind(port).sync();            //阻塞等待， 等待服务端监听端口关闭            f.channel().closeFuture().sync();        } finally {            //释放线程池资源            bossGroup.shutdownGracefully();            workerGroup.shutdownGracefully();        }    }    private class ChildChannelHandler extends ChannelInitializer<SocketChannel> {        @Override        protected void initChannel(SocketChannel arg0) throws Exception {            //创建NioSocketChannel成功之后，初始化的时候将它的SocketChannel设置到ChannelPipeline中用于处理网络IO事件。            arg0.pipeline().addLast(new TimeServerHandler());        }    }    public static void main(String[] args) throws Exception {        int port = 8080;        new TimeServer().bind(port);    }}

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;public class TimeServerHandler extends ChannelHandlerAdapter {    @Override    public void channelRead(ChannelHandlerContext ctx, Object msg)            throws Exception {        //读取信息        ByteBuf buf = (ByteBuf) msg;        byte[] req = new byte[buf.readableBytes()];//获取缓冲区可读的字节数，根据字节数创建byte数组，        buf.readBytes(req);//将缓冲区的字节数组复制到新建的字节数组中，        String body = new String(req, "UTF-8");        System.out.println("客服端发来的信息：" + body);        //发送信息        Date time = new Date();        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");        String s = simpleDateFormat.format(time);        String str = body + s;        ByteBuf resp = Unpooled.copiedBuffer(str.getBytes());        ctx.write(resp);//异步将信息发送给客服端    }    @Override    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {        ctx.flush();//将消息发送列队中的消息写入到SocketChannel中发送给对方    }    @Override    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {        System.out.print("异常");        ctx.close();//关闭资源    }}

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