Netty-搭建简单事件服务器

1、服务端：

package com.suirui.server;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.ServerSocketChannel;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;


/**
 * Created by zongx on 2019/12/26.
 */
public class TimeServer {

    public static void main(String[] args) {
        int port = 9999;
        if (args != null && args.length > 0) {
            port = Integer.valueOf(args[0]);
        }
        new TimeServer().bind(port);
    }

    public void bind(int port) {
        //配置服务端的NIO线程组
        //两个线程组的原因是：
        // 一个用于服务端接收客户端连接
        //一个用于进行socketChannel网络读写
        NioEventLoopGroup bossGroup = new NioEventLoopGroup();
        NioEventLoopGroup workerGroup = new NioEventLoopGroup();
        //ServerBootstrap 是netty的辅助启动类
        ServerBootstrap b = new ServerBootstrap();
        // .group传入两个线程组
        // .channel设置创建的Channel类型为NioServerSocketChannel
        // .option 配置NioServerSocketChannel的TCP参数
        // .childHandler绑定IO事件的处理类 类似reactor模式中的handler:进行连接与读写socket。
        // ChildChannelHandler会重写initChannel，保证当创建NioServerSocketChannel成功之后，再进行初始化。
        /*************.handler 与   .childHandler的区别*******/
        // handler()和childHandler()的主要区别是，handler()是发生在初始化的时候，childHandler()是发生在客户端连接之后。
        b.group(bossGroup,workerGroup)
                .channel(NioServerSocketChannel.class)
                .option(ChannelOption.SO_BACKLOG, 1024)
                .childHandler(new ChildChannelHandler());
        //绑定端口，等待成功
        try {
            //.sync()是同步阻塞接口，等待绑定操作完成
            //ChannelFuture主要用于异步操作的通知回调
            ChannelFuture f = b.bind(port).sync();
            //等待服务端监听端口关闭
            f.channel().closeFuture().sync();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }finally {
            //释放线程池资源
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }


    }

    private class ChildChannelHandler extends ChannelInitializer {
        //注意此处不要使用ServerSocketChannel，否则客户端无法启动端口
        @Override
        protected void initChannel(SocketChannel ch) throws Exception {
            ch.pipeline().addLast(new TimeServerHandler());
        }
    }
}

package com.suirui.server;


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

import java.nio.ByteBuffer;
import java.time.LocalDateTime;

/**
 * Created by zongx on 2019/12/26.
 */
public class TimeServerHandler extends SimpleChannelInboundHandler {

    private int count =0;

    @Override
    protected void channelRead0(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("TimeServer 收到指令： " + body +  ", 当前次数 ：" + count++);
        String currentTime = "query time order".equalsIgnoreCase(body)? LocalDateTime.now().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();
    }
}

 

2、客户端

package com.suirui.client;

import com.suirui.server.TimeServerHandler;
import io.netty.bootstrap.Bootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioSocketChannel;


/**
 * Created by zongx on 2019/12/26.
 */
public class TimeClient {

    public static void main(String[] args) throws Exception {
        int port = 9999;
        if (args != null && args.length > 0) {
            port = Integer.valueOf(args[0]);
        }
        new TimeClient().connect("127.0.0.1", port);
    }

    private void connect(String host, int port) throws Exception {
        //配置客户端NIO线程组
        NioEventLoopGroup group = new NioEventLoopGroup();
        Bootstrap b = new Bootstrap();
        b.group(group)
                .channel(NioSocketChannel.class)
                .option(ChannelOption.TCP_NODELAY, true)
                .handler(new ChildChannelHandler());
        //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();
    }

    private class ChildChannelHandler extends ChannelInitializer {

        @Override
        protected void initChannel(SocketChannel ch) throws Exception {
            ch.pipeline().addLast(new TimeClientHandler());
        }
    }
}


package com.suirui.client;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandler;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;

/**
 * Created by zongx on 2019/12/26.
 */
public class TimeClientHandler extends SimpleChannelInboundHandler {

    private final byte[] order;

    private int count = 0;

    public TimeClientHandler() {
        order = "query time order".getBytes();
        
    }

    @Override
    protected void channelRead0(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("当前时间为： " + body + ", 当前次数 " + count++);
        System.out.println();
        System.out.println();
        System.out.println();
        Thread.sleep(1000);
        ByteBuf firstMessage = Unpooled.buffer(order.length);
        firstMessage.writeBytes(order);
        ctx.writeAndFlush(firstMessage);
    }

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
//        for (int i = 0; i < 100; i++) {
            ByteBuf firstMessage = Unpooled.buffer(order.length);
            firstMessage.writeBytes(order);
            ctx.writeAndFlush(firstMessage);
//        }

    }

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

结果：