netty入门demo

参考博客：(14条消息) 【Netty整理01-快速入门】Netty简单使用Demo（已验证）_the_fool_的博客-CSDN博客

ServerHandler.java

package com.hmb;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;

public class ServerHandler extends ChannelInboundHandlerAdapter {
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        System.out.println("server read....");
        ByteBuf buf = (ByteBuf) msg;
        byte[] date = new byte[buf.readableBytes()];
        buf.readBytes(date);
        System.out.println("client msg: " + new String(date));
        buf.release();

        System.out.println("send msg to client...");
        String response = "hello client";
        ByteBuf buf1 = ctx.alloc().buffer();
        buf1.writeBytes(response.getBytes());
        ctx.write(buf1);
        ctx.flush();
    }

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

NettyServer.java

package com.hmb;

import io.netty.bootstrap.Bootstrap;
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 NettyServer {
    private int port = 9999;

    public void start() {
        EventLoopGroup worker = new NioEventLoopGroup();
        EventLoopGroup boss = new NioEventLoopGroup();

        ServerBootstrap serverBootstrap = new ServerBootstrap();
        serverBootstrap.group(boss, worker)
                .option(ChannelOption.SO_BACKLOG, 1024)
                .option(ChannelOption.SO_KEEPALIVE, true)
                .channel(NioServerSocketChannel.class)
                .childHandler(new ChannelInitializer<SocketChannel>() {
                    @Override
                    protected void initChannel(SocketChannel socketChannel) throws Exception {
                        socketChannel.pipeline().addLast(new ServerHandler());
                    }
                });

        try {
            ChannelFuture cf = serverBootstrap.bind(port).sync();
            cf.channel().closeFuture() .sync();
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        } finally {
            boss.shutdownGracefully();
            worker.shutdownGracefully();
        }
    }

    public static void main(String[] args) {
        NettyServer server = new NettyServer();
        server.start();
    }
}

ClientHandler.java

package com.hmb;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;

public class ClientHandler extends ChannelInboundHandlerAdapter {
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        System.out.println("read msg from server...");
        ByteBuf buf = (ByteBuf) msg;
        byte[] date = new byte[buf.readableBytes()];
        buf.readBytes(date);
        System.out.println("server msg: " + new String(date));
        buf.release();

        Thread.sleep(10000);
        System.out.println("send msg to server...");
        String response = "hello server";
        ByteBuf buf1 = ctx.alloc().buffer();
        buf1.writeBytes(response.getBytes());
        ctx.write(buf1);
        ctx.flush();
    }

    /**
     * channel生命周期回调函数，channel准备好后回调此函数，不能少，否则bs交互无法发起
     * @param ctx
     * @throws Exception
     */
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        System.out.println("firstly send msg to server...");
        String msg = "hello server!";
        ByteBuf encode = ctx.alloc().buffer(4 * msg.length());
        encode.writeBytes(msg.getBytes());
        ctx.write(encode);
        ctx.flush();
    }
}

NettyClient.java

package com.hmb;

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 NettyClient {
    public void connect(String host, int port) {
        EventLoopGroup worker = new NioEventLoopGroup();
        Bootstrap bootstrap = new Bootstrap();
        bootstrap.group(worker)
                .channel(NioSocketChannel.class)
                .option(ChannelOption.SO_KEEPALIVE, true)
                .handler(new ChannelInitializer<SocketChannel>() {
                    @Override
                    protected void initChannel(SocketChannel socketChannel) throws Exception {
                        socketChannel.pipeline().addLast(new ClientHandler());
                    }
                });

        try {
            ChannelFuture channelFuture = bootstrap.connect(host, port).sync();
            channelFuture.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        } finally {
            worker.shutdownGracefully();
        }
    }

    public static void main(String[] args) {
        NettyClient nettyClient = new NettyClient();
        nettyClient.connect("127.0.0.1", 9999);
    }
}

先运行NettyServer.java的main方法，再运行NettyClient.java的main方法，此时就可以看到bs的交互信息