服务端

/**
 * 服务端
 * @author suibibk@qq.com
 */
public class NettyServer {
    public static void main(String[] args) throws Exception{
        //1、创建一个线程组，接收客户端连接
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        //2、创建一个线程组，处理网络操作
        EventLoopGroup workerGroup = new NioEventLoopGroup();
        //3、创建服务端启动助手来配置参数
        ServerBootstrap b = new ServerBootstrap();
        b.group(bossGroup, workerGroup)//4、设置两个线程组
         .channel(NioServerSocketChannel.class)//5、使用NioServerSocketChannel作为服务器端通道的实现
         .option(ChannelOption.SO_BACKLOG, 128)//6、设置线程队列中等待连接的个数
         .childOption(ChannelOption.SO_KEEPALIVE, true)//7、保持活动连接状态
         .childHandler(new ChannelInitializer<SocketChannel>() {//8、创建一个通道初始化对象
            @Override
            protected void initChannel(SocketChannel sc) throws Exception {
                //9、往pipeline链中添加自定义的handler
                sc.pipeline().addLast(new NettyServerHandler());
            }
         });
        System.out.print("Server is ready.....");
        ChannelFuture cf = b.bind(9999).sync();//10、绑定端口，bind方法是异步的，sync方法是同步阻塞的
        System.out.print("Server is starting.....");
        //11、关闭通道，关闭线程组
        cf.channel().closeFuture().sync();//关闭连接(异步非阻塞)
        bossGroup.shutdownGracefully();
        workerGroup.shutdownGracefully();
        System.out.print("Server is end.....");
    }
}

记得要用

import io.netty.channel.socket.SocketChannel;

用这个会报下面的错误

import java.nio.channels.SocketChannel;

Bound mismatch: The type SocketChannel is not a valid substitute for the bounded parameter <C extends Channel> of the type ChannelInitializer<C>

服务端处理业务类

/**
 * 服务端处理业务类
 * @author suibibk@qq.com
 *
 */
public class NettyServerHandler extends ChannelInboundHandlerAdapter{
    //读取数据事件
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        System.out.println("Server :"+ctx);
        ByteBuf buf = (ByteBuf)msg;
        System.out.println("客户端发来的消息："+buf.toString(CharsetUtil.UTF_8));
    }
    //数据读取完毕事件
    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
        ctx.writeAndFlush(Unpooled.copiedBuffer("疫情太严重，我没有钱", CharsetUtil.UTF_8));
    }
    //异常发生事件
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        System.out.println(cause.getMessage());
        ctx.close();
    }
}

客户端

/**
 * 网络客户端
 * @author suibibk@qq.com
 *
 */
public class NettyClient {
    public static void main(String[] args)throws Exception {
        //1、创建一个线程组
        EventLoopGroup group = new NioEventLoopGroup();
        //2、创建客户端启动助手，完成相关配置
        Bootstrap b = new Bootstrap();
        b.group(group)//3、设置线程组
         .channel(NioSocketChannel.class)//4、设置客户端通道的实现类
         .handler(new ChannelInitializer<SocketChannel>() {//创建一个初始化通道对象
            @Override
            protected void initChannel(SocketChannel sc) throws Exception {
                //6、在pipline中添加自定义的handler
                sc.pipeline().addLast(new NettyClientHandler());
            }
         });
        System.out.println("Client is ready");
        //7、启动客户端去连接服务器端 connect方法是异步的，sync方法是同步阻塞的
        ChannelFuture cf =b.connect("127.0.0.2", 9999).sync();
        //8、关闭连接（异步非阻塞）
        cf.channel().closeFuture().sync();
        System.out.print("Client is end.....");
    }
}

客户端处理业务类

/**
 * 客户端业务处理类
 * @author suibibk@qq.com
 *
 */
public class NettyClientHandler extends ChannelInboundHandlerAdapter{
    //通道就绪时间
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        System.out.println("Client"+ctx);
        ctx.writeAndFlush(Unpooled.copiedBuffer("老板还钱吧", CharsetUtil.UTF_8));
    }
    //读取数据事件
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        ByteBuf buf = (ByteBuf)msg;
        System.out.println("服务端发来的消息："+buf.toString(CharsetUtil.UTF_8));
    }
}