ccDangJianExam/src/main/java/com/dsideal/FengHuang/Util/SocketUtil.java

package com.dsideal.FengHuang.Util;

import io.netty.bootstrap.Bootstrap;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.*;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.handler.codec.MessageToByteEncoder;

import java.nio.charset.StandardCharsets;

public class SocketUtil {
    private final String host;
    private final int port;

    public SocketUtil(String host, int port) {
        this.host = host;
        this.port = port;
    }

    public void sendHexData(String hexData) throws Exception {
        EventLoopGroup workerGroup = new NioEventLoopGroup();

        try {
            Bootstrap b = new Bootstrap();
            b.group(workerGroup);
            b.channel(NioSocketChannel.class);
            b.option(ChannelOption.SO_KEEPALIVE, true);
            b.handler(new ChannelInitializer<SocketChannel>() {
                @Override
                public void initChannel(SocketChannel ch) {
                    ChannelPipeline p = ch.pipeline();
                    p.addLast(new HexDataEncoder());
                    p.addLast(new HexDataSenderHandler(hexData));
                    p.addLast(new ClientHandler()); // 添加客户端 Handler
                }
            });

            // Start the client.
            ChannelFuture f = b.connect(host, port).sync();
            // Wait until the connection is closed.
            //f.channel().closeFuture().sync();
            //手动关闭
            f.channel().close();
        } finally {
            workerGroup.shutdownGracefully();
        }
    }

    class HexDataSenderHandler extends ChannelInboundHandlerAdapter {
        private final String hexData;

        public HexDataSenderHandler(String hexData) {
            this.hexData = hexData;
        }

        @Override
        public void channelActive(ChannelHandlerContext ctx) {
            byte[] bytes = hexStringToByteArray(hexData);
            ByteBuf buffer = Unpooled.buffer(bytes.length);
            buffer.writeBytes(bytes);
            ctx.writeAndFlush(buffer);
        }

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

        private byte[] hexStringToByteArray(String hexData) {
            int len = hexData.length();
            byte[] data = new byte[len / 2];
            for (int i = 0; i < len; i += 2) {
                data[i / 2] = (byte) ((Character.digit(hexData.charAt(i), 16) << 4) +
                        Character.digit(hexData.charAt(i + 1), 16));
            }
            return data;
        }


    }

    static class ClientHandler extends ChannelInboundHandlerAdapter {

        @Override
        public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
            // 处理服务器响应数据
            byte[] bytes = (byte[]) msg;
            String response = new String(bytes, StandardCharsets.US_ASCII);
            System.out.println("Server response: " + response);
        }

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

    static class HexDataEncoder extends MessageToByteEncoder<ByteBuf> {
        @Override
        protected void encode(ChannelHandlerContext ctx, ByteBuf msg, ByteBuf out) throws Exception {
            byte[] bytes = new byte[msg.readableBytes()];
            msg.getBytes(msg.readerIndex(), bytes);
            out.writeBytes(bytes);
        }
    }

}