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