从零开始手写mmo游戏从框架到爆炸（八）— byte数组传输

导航：从零开始手写mmo游戏从框架到爆炸（零）—— 导航-CSDN博客   

Netty帧解码器

        Netty中，提供了几个重要的可以直接使用的帧解码器。

LineBasedFrameDecoder

       行分割帧解码器。适用场景：每个上层数据包，使用换行符或者回车换行符做为边界分割符。发送端发送的时候，每个数据包之间以换行符/回车换行符作为分隔。在这种场景下，只需要把这个解码器加到 pipeline 中，Netty 会使用换行分隔符，把底层帧分割成一个一个完整的应用层数据包，发送到下一站。

FixedLengthFrameDecoder

        固定长度帧解码器。适用场景：每个上层数据包的长度，都是固定的，比如 100。在这种场景下，只需要把这个解码器加到 pipeline 中，Netty 会把底层帧，拆分成一个个长度为 100 的数据包 (ByteBuf)，发送到下一个 channelHandler入站处理器。

DelimiterBasedFrameDecoder

        自定义分隔符帧解码器 。DelimiterBasedFrameDecoder 是LineBasedFrameDecoder的通用版本。不同之处在于，这个解码器，可以自定义分隔符，而不是局限于换行符。如果使用这个解码器，在发送的时候，末尾必须带上对应的分隔符。

LengthFieldBasedFrameDecoder

        自定义长度帧解码器。这是一种基于灵活长度的解码器。在数据包中，加了一个长度字段（长度域），保存上层包的长度。解码的时候，会按照这个长度，进行上层ByteBuf应用包的提取。

        我们之前使用的是自定义分隔符帧解码器，现在我们改用自定义长度帧解码器。LengthFieldBasedFrameDecoder有几个参数，我们看一起看一下：

• lengthFieldOffset 长度域的偏移量，简单而言就是偏移几个字节是长度域
• lengthFieldLength ： 长度域的所占的字节数
• lengthAdjustment ： 长度值的调整值
• initialBytesToStrip ： 需要跳过的字节数

参考：LengthFieldBasedFrameDecoder 详解-CSDN博客  

现在我们就来修改编解码器，同时修改相关的类。

byte数组传输

        前两章我们已经完成了对消息体的封装和编解码器，然后我们来修改相关的代码，其实就是把原来string类型改为StringMessage类型

TcpMessageStringHandler.java

import com.loveprogrammer.base.network.listener.INetworkEventListener;
import com.loveprogrammer.base.network.support.SessionManager;
import com.loveprogrammer.pojo.StringMessage;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Scope;
import org.springframework.stereotype.Component;/*** @ClassName TcpMessageStringHandler* @Description tcp消息处理类* @Author admin* @Date 2024/2/4 15:16* @Version 1.0*/
@Component
@Scope("prototype")
public class TcpMessageStringHandler extends SimpleChannelInboundHandler<StringMessage> {private static final Logger logger = LoggerFactory.getLogger(TcpMessageStringHandler.class);@Autowiredprivate INetworkEventListener listener;//    public TcpMessageStringHandler(INetworkEventListener listener) {
//        this.listener = listener;
//    }@Overridepublic void exceptionCaught(ChannelHandlerContext ctx, Throwable throwable) {listener.onExceptionCaught(ctx,throwable);}@Overridepublic void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {super.channelRead(ctx, msg);}@Overrideprotected void channelRead0(ChannelHandlerContext ctx, StringMessage msg) {listener.channelRead(ctx,msg);// ctx.writeAndFlush(result);}@Overridepublic void channelActive(ChannelHandlerContext ctx) throws Exception {listener.onConnected(ctx);}@Overridepublic void channelInactive(ChannelHandlerContext ctx) throws Exception {listener.onDisconnected(ctx);}
}

TcpServerStringInitializer.java

import com.loveprogrammer.base.factory.SpringContextHelper;
import com.loveprogrammer.base.network.listener.INetworkEventListener;
import com.loveprogrammer.base.network.support.NetworkListener;
import com.loveprogrammer.codec.MessageDecoder;
import com.loveprogrammer.codec.MessageEncoder;
import com.loveprogrammer.constants.ConstantValue;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.DelimiterBasedFrameDecoder;
import io.netty.handler.codec.Delimiters;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;public class TcpServerStringInitializer extends ChannelInitializer<SocketChannel> {@Overrideprotected void initChannel(SocketChannel ch) {ChannelPipeline pipeline = ch.pipeline();// pipeline.addLast("framer",new DelimiterBasedFrameDecoder(8192, Delimiters.lineDelimiter()));pipeline.addLast("decoder", new MessageEncoder());pipeline.addLast("encoder", new MessageDecoder(ConstantValue.MESSAGE_CODEC_MAX_FRAME_LENGTH,ConstantValue.MESSAGE_CODEC_LENGTH_FIELD_OFFSET, ConstantValue.MESSAGE_CODEC_LENGTH_FIELD_LENGTH,ConstantValue.MESSAGE_CODEC_LENGTH_ADJUSTMENT, ConstantValue.MESSAGE_CODEC_INITIAL_BYTES_TO_STRIP, false));TcpMessageStringHandler handler = (TcpMessageStringHandler) SpringContextHelper.getBean(TcpMessageStringHandler.class);pipeline.addLast(handler);}}

INetworkEventListener.java

public interface INetworkEventListener {/*** 连接建立** @param ctx ChannelHandlerContext*/void onConnected(ChannelHandlerContext ctx);/*** 连接断开* * @param ctx ChannelHandlerContext*/void onDisconnected(ChannelHandlerContext ctx);/*** 异常发生* * @param ctx ChannelHandlerContext* * @param throwable 异常*/void onExceptionCaught(ChannelHandlerContext ctx, Throwable throwable);void channelRead(ChannelHandlerContext ctx, StringMessage msg);}

NetworkListener.java

package com.loveprogrammer.base.network.support;import com.loveprogrammer.base.bean.session.Session;
import com.loveprogrammer.base.network.listener.INetworkEventListener;
import com.loveprogrammer.constants.CommonValue;
import com.loveprogrammer.pojo.StringMessage;
import io.netty.channel.ChannelHandlerContext;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;@Component
public class NetworkListener implements INetworkEventListener {protected static final Logger logger = LoggerFactory.getLogger(NetworkListener.class);@Overridepublic void onConnected(ChannelHandlerContext ctx) {logger.info("建立连接");SessionManager.getInstance().create(ctx.channel());}@Overridepublic void onDisconnected(ChannelHandlerContext ctx) {logger.info("建立断开");SessionManager.getInstance().close(ctx.channel());}@Overridepublic void onExceptionCaught(ChannelHandlerContext ctx, Throwable throwable) {logger.warn("异常发生", throwable);}@Overridepublic void channelRead(ChannelHandlerContext ctx, StringMessage msg) {logger.info("数据内容：data=" + msg.getBody());String result = "我是服务器，我收到了你的信息:" + msg.getBody();Session session = SessionManager.getInstance().getSessionByChannel(ctx.channel());result += ",sessionId = " + session.getId();StringMessage message = StringMessage.create(1,1);message.setStatusCode(CommonValue.MSG_STATUS_CODE_SUCCESS);message.setBody(result);SessionManager.getInstance().sendMessage(ctx.channel(),message);}
}

同样的client端也要跟着修改一下

SocketClient

public class SocketClient {private static final Logger logger = LoggerFactory.getLogger(SocketClient.class);private static final String IP = "127.0.0.1";private static final int PORT = 8088;private static EventLoopGroup group = new NioEventLoopGroup();protected static void run() throws InterruptedException {
//        Bootstrap bootstrap = new Bootstrap();
//        bootstrap.group(group);
//        bootstrap.channel(NioSocketChannel.class);
//        bootstrap.handler(new ChannelInitializer() {
//            protected void initChannel(Channel ch) throws Exception {
//                ChannelPipeline pipeline = ch.pipeline();
//                pipeline.addLast("framer",new DelimiterBasedFrameDecoder(8192, Delimiters.lineDelimiter()));
//                pipeline.addLast("decoder",new StringDecoder());
//                pipeline.addLast("encoder",new StringEncoder());
//                pipeline.addLast(new SocketClientHandler());
//            }
//        });Bootstrap bootstrap = new Bootstrap();bootstrap.group(group);bootstrap.channel(NioSocketChannel.class);bootstrap.handler(new ChannelInitializer() {@Overrideprotected void initChannel(Channel ch) {ChannelPipeline pipeline = ch.pipeline();pipeline.addLast("encoder", new MessageEncoder());pipeline.addLast("decoder", new MessageDecoder(ConstantValue.MESSAGE_CODEC_MAX_FRAME_LENGTH,ConstantValue.MESSAGE_CODEC_LENGTH_FIELD_LENGTH, ConstantValue.MESSAGE_CODEC_LENGTH_FIELD_OFFSET,ConstantValue.MESSAGE_CODEC_LENGTH_ADJUSTMENT, ConstantValue.MESSAGE_CODEC_INITIAL_BYTES_TO_STRIP,false));pipeline.addLast(new SocketClientHandler());}});// 连接服务器ChannelFuture channelFuture = bootstrap.connect(IP, PORT).sync();StringMessage msg = StringMessage.create(1,1);msg.setStatusCode(200);msg.setBody("你好，我是eric");// msg += "\r\n";channelFuture.channel().writeAndFlush(msg);logger.info("向服务器发送消息 {}",msg);channelFuture.channel().closeFuture().sync();}public static void main(String[] args) throws InterruptedException {logger.info("开始连接Socket服务器...");try {run();} catch (Exception e) {e.printStackTrace();} finally {group.shutdownGracefully();}}}

SocketClientHandler.java

import com.loveprogrammer.pojo.StringMessage;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;/*** @ClassName SocketClientHandler* @Description TODO* @Author admin* @Date 2024/1/29 17:41* @Version 1.0*/
public class SocketClientHandler extends SimpleChannelInboundHandler<StringMessage> {private static final Logger logger = LoggerFactory.getLogger(SocketClientHandler.class);@Overridepublic void exceptionCaught(ChannelHandlerContext arg0, Throwable arg1) {logger.info("异常发生", arg1);}@Overridepublic void channelRead(ChannelHandlerContext arg0, Object msg) throws Exception {super.channelRead(arg0, msg);}@Overrideprotected void channelRead0(ChannelHandlerContext context, StringMessage data) {logger.info("数据内容：data=" + data);try {Thread.sleep(1000);} catch (InterruptedException e) {e.printStackTrace();}StringMessage msg = StringMessage.create(1,1);msg.setStatusCode(202);msg.setBody("你好，我是eric");// msg += "\r\n";context.channel().writeAndFlush(msg);logger.info("向服务器发送消息 {}",msg);}@Overridepublic void channelActive(ChannelHandlerContext ctx) throws Exception {logger.info("客户端连接建立");super.channelActive(ctx);}@Overridepublic void channelInactive(ChannelHandlerContext ctx) throws Exception {logger.info("客户端连接断开");super.channelInactive(ctx);}}

全部源码详见：

gitee : eternity-online: 多人在线mmo游戏 - Gitee.com

分支：step-06