Netty框架快速入門

NIO 客戶端服務器框架，快速簡單開發網絡應用程序，如協議服務器和客戶端。自定義設計和實現一個全新的協議。文章參考Nettty官網

快速入門：最簡單的通信協議服務 -- Discard Server

• Discard：丟棄任何接收到的數據
• 項目準備：maven依賴

        <dependency>
            <groupId>io.netty</groupId>
            <artifactId>netty-all</artifactId>
            <version>4.1.50.Final</version>
        </dependency>

• 信道編寫：用於處理接收數據後的業務

package com.ht.server;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.util.CharsetUtil;
import io.netty.util.ReferenceCountUtil;

/**
 * Discard 協議服務信道
 *
 * @author: liht
 * @date: 2021/7/8-10:26
 */
public class DiscardServerHandler extends ChannelInboundHandlerAdapter {

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        // todo: 打印丟棄接收到的數據
        ByteBuf in = (ByteBuf) msg;
        while (in.isReadable()){
            System.out.println(in.toString(CharsetUtil.US_ASCII));
        }
        ReferenceCountUtil.release(msg);
/*        // todo: 將接收到的數據發回
        ctx.writeAndFlush(msg);*/
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        // 程序異常時，關閉信道
        cause.printStackTrace();
        ctx.close();
    }
}

• 啓動服務類

package com.ht.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.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;

/**
 * Discard 服務啓動類
 *
 * @author: liht
 * @date: 2021/7/8-10:48
 */
public class DiscardServer {
    /**
     * 端口
     */
    private int port;
    /**
     * Ip地址
     */
    private String ip;

    public DiscardServer(int port) {
        this.port = port;
    }

    public DiscardServer(int port, String ip) {
        this.port = port;
        this.ip = ip;
    }

    private void run() throws Exception{
        // 多線程循環，接收傳入的連接
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workerGroup = new NioEventLoopGroup();

        // 設置服務助手類
        ServerBootstrap bootstrap = new ServerBootstrap();
        bootstrap.group(bossGroup, workerGroup)
                .channel(NioServerSocketChannel.class)
                .childHandler(new ChannelInitializer<SocketChannel>() {
                    @Override
                    protected void initChannel(SocketChannel ch) {
                        ch.pipeline().addLast(new DiscardServerHandler());
                    }
                })
                .option(ChannelOption.SO_BACKLOG, 128)
                .childOption(ChannelOption.SO_KEEPALIVE, true);

        // 綁定端口，啓動連接
        ChannelFuture cf = bootstrap.bind(port).sync();
        // 關閉服務
        cf.channel().closeFuture().sync();

        workerGroup.shutdownGracefully();
        bossGroup.shutdownGracefully();
    }


    public static void main(String[] args) throws Exception {
        int port = 8080;
        new DiscardServer(port).run();
    }
}

• 使用postman 推送數據測試...