高性能nio通信框架之netty入门(代码片段)

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;

/**
 * Netty 时间服务器服务端TimeServer
 */
public class TimeServer 
    public void bind(int port) 
        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).childHandler(new ChildChannelHandler());
            //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) 
            e.printStackTrace();
         finally 
            //优雅退出，释放线程池资源
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        
    

    private class ChildChannelHandler extends ChannelInitializer<SocketChannel> 

        @Override
        protected void initChannel(SocketChannel socketChannel) throws Exception 
            socketChannel.pipeline().addLast(new TimeServerHandler());
        
    

    public static void main(String[] args) 
        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.util.Date;


public class TimeServerHandler extends ChannelHandlerAdapter

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception 
        ByteBuf buf = (ByteBuf) msg;
        byte[] req = new byte[buf.readableBytes()];
        buf.readBytes(req);
        String body = new String(req,"UTF-8");
        System.out.println("The time server receive order : "+body);
        String currentTime = "QUERY TIME ORDER".equalsIgnoreCase(body)?new Date(System.currentTimeMillis()).toString():"BAD ORDER";
        ByteBuf resp = Unpooled.copiedBuffer(currentTime.getBytes());
        ctx.write(resp);
    

    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception 
        ctx.flush();
    

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception 
        ctx.close();
    

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 ThinkPad on 2019/6/17.
 */
public class TimeClient 
    public void connect(int port,String host) 
        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 socketChannel) throws Exception 
                    socketChannel.pipeline().addLast(new TimeClientHandler());
                
            );
            //发起异步连接操作
            ChannelFuture f = b.connect(host,port).sync();
            //等待客户端连接操作
            f.channel().closeFuture().sync();
        catch (Exception e) 
            e.printStackTrace();
        finally 
            //优雅退出，释放NIO线程组
            group.shutdownGracefully();
        
    

    public static void main(String[] args) 
        int port = 8080;
        new TimeClient().connect(port,"127.0.0.1");
    






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

/**
 * Created by ThinkPad on 2019/6/17.
 */
public class TimeClientHandler extends ChannelHandlerAdapter
    private final ByteBuf firstMessage;

    public TimeClientHandler() 
        byte[] req = "QUERY TIME ORDER".getBytes();
        firstMessage = Unpooled.buffer(req.length);
        firstMessage.writeBytes(req);
    

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception 
        ctx.writeAndFlush(firstMessage);
    

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception 
        ByteBuf buf = (ByteBuf)msg;
        byte[] req = new byte[buf.readableBytes()];
        buf.readBytes(req);
        String body = new String(req,"UTF-8");
        System.out.println("Now is : "+body);
    

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception 
        ctx.close();