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 {
private static final Logger logger = LoggerFactory.getLogger(TcpMessageStringHandler.class);
@Autowired
private INetworkEventListener listener;
// public TcpMessageStringHandler(INetworkEventListener listener) {
// this.listener = listener;
// }
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable throwable) {
listener.onExceptionCaught(ctx,throwable);
}
@Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
super.channelRead(ctx, msg);
}
@Override
protected void channelRead0(ChannelHandlerContext ctx, StringMessage msg) {
listener.channelRead(ctx,msg);
// ctx.writeAndFlush(result);
}
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
listener.onConnected(ctx);
}
@Override
public 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 {
@Override
protected 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);
@Override
public void onConnected(ChannelHandlerContext ctx) {
logger.info("建立连接");
SessionManager.getInstance().create(ctx.channel());
}
@Override
public void onDisconnected(ChannelHandlerContext ctx) {
logger.info("建立断开");
SessionManager.getInstance().close(ctx.channel());
}
@Override
public void onExceptionCaught(ChannelHandlerContext ctx, Throwable throwable) {
logger.warn("异常发生", throwable);
}
@Override
public 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() {
@Override
protected 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 {
private static final Logger logger = LoggerFactory.getLogger(SocketClientHandler.class);
@Override
public void exceptionCaught(ChannelHandlerContext arg0, Throwable arg1) {
logger.info("异常发生", arg1);
}
@Override
public void channelRead(ChannelHandlerContext arg0, Object msg) throws Exception {
super.channelRead(arg0, msg);
}
@Override
protected 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);
}
@Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
logger.info("客户端连接建立");
super.channelActive(ctx);
}
@Override
public 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