NIO（六）--Netty-hello world

一、概念

Netty學習路線總結

netty是nio架構。

任何nio架構做通信，一定是server先啟動，然後，client端調用connect方法。

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 Server {

    public static void main(String[] args) throws InterruptedException {

        EventLoopGroup bossGroup = new NioEventLoopGroup();         //一個用于處理伺服器端接收用戶端連接配接的
        EventLoopGroup workGroup = new NioEventLoopGroup();         //一個是進行網絡通信的（網絡讀寫的）
        ServerBootstrap b = new ServerBootstrap();                  //2建立輔助工具類，用于伺服器通道的一系列配置
        b.group(bossGroup, workGroup)                               //綁定兩個線程組
                .channel(NioServerSocketChannel.class)              //指定NIO的模式
                .option(ChannelOption.SO_BACKLOG, 1024)             //設定tcp緩沖區
                .option(ChannelOption.SO_SNDBUF, 32 * 1024)         //設定發送緩沖大小
                .option(ChannelOption.SO_RCVBUF, 32 * 1024)         //這是接收緩沖大小
                .option(ChannelOption.SO_KEEPALIVE, true)           //保持連接配接
                .childHandler(new ChannelInitializer<SocketChannel>() {
                    @Override
                    protected void initChannel(SocketChannel sc) throws Exception {
                        sc.pipeline().addLast(new ServerHanlder()); //3.在這裡配置具體資料接收方法的處理
                    }
                });

        ChannelFuture cf1 = b.bind(6666).sync();                    //4.進行綁定
        cf1.channel().closeFuture().sync();                         //5.等待關閉

        bossGroup.shutdownGracefully();
        workGroup.shutdownGracefully();

    }
}
           

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

public class ServerHanlder 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("Server: " + body);
        String response = "888";//服務端給用戶端的響應
        ctx.writeAndFlush(Unpooled.copiedBuffer(response.getBytes()));
    }

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

import io.netty.bootstrap.Bootstrap;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
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 Client {
    public static void main(String[] args) throws InterruptedException {
        EventLoopGroup group = new NioEventLoopGroup();
        Bootstrap b = new Bootstrap();
        b.group(group)
                .channel(NioSocketChannel.class)
                .handler(new ChannelInitializer<SocketChannel>() {
                    @Override
                    protected void initChannel(SocketChannel sc) throws Exception {
                        sc.pipeline().addLast(new ClientHandler());
                    }
                });

        ChannelFuture cf1 = b.connect("127.0.0.1", 6666).sync();

        cf1.channel().write(Unpooled.copiedBuffer("777".getBytes()));   //用戶端發出資料
        cf1.channel().flush();

        cf1.channel().closeFuture().sync();
        group.shutdownGracefully();
    }
}
           

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerAdapter;
import io.netty.channel.ChannelHandlerContext;
import io.netty.util.ReferenceCountUtil;

public class ClientHandler extends ChannelHandlerAdapter {

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {

        try {
            ByteBuf buf = (ByteBuf) msg;
            byte[] req = new byte[buf.readableBytes()];
            buf.readBytes(req);
            String body = new String(req, "utf-8");
            System.out.println("Client: " + body);
        } finally {
            ReferenceCountUtil.release(msg);
        }
    }

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

如何斷開用戶端的連接配接？

開啟多個端口