企业官网建设流程全解析

上一篇【第52篇】Netty秒杀系统——高并发网络接入层实战
下一篇【第54篇】Netty在Elasticsearch中的应用——分布式搜索引擎的网络通信

一、Dubbo网络通信架构

+------------------+ +------------------+ | Consumer | | Provider | | (NettyClient) | | (NettyServer) | +------------------+ +------------------+ | Transport层 | | Transport层 | | Exchange层 | | Exchange层 | | Protocol层 | | Protocol层 | +------------------+ +------------------+ | | +----------------------+ | Dubbo协议（基于Netty）

二、Dubbo协议格式

Dubbo RPC协议帧： +------+------+------+------+------+------+------+------+ | 魔数(0xdabb,2B) | 标志位(1B) | 状态(1B) | ID(8B) | +------+------+------+------+------+------+------+------+ | 数据长度(4B) | +------+------+------+------+------+------+------+------+ | 序列化数据(body, variable) | +------+------+------+------+------+------+------+------+

标志位含义：

• bit 0-2：序列化类型(0=Hessian, 2=JSON, 6=Kryo, 8=Protobuf)
• bit 3-4：事件类型(0=Request, 1=Response, 2=心跳)
• bit 5：是否双向通信
• bit 6-7：保留

三、NettyServer初始化

// Dubbo 3.x中的NettyServerpublicclassNettyServerextendsAbstractServer{protectedvoiddoOpen(){bootstrap=newServerBootstrap();bootstrap.group(bossGroup,workerGroup).channel(NioServerSocketChannel.class).childOption(ChannelOption.TCP_NODELAY,true).childOption(ChannelOption.SO_KEEPALIVE,true).childHandler(newChannelInitializer<SocketChannel>(){protectedvoidinitChannel(SocketChannelch){// Dubbo编解码器ch.pipeline().addLast("decoder",newDubboCountCodec());ch.pipeline().addLast("encoder",newDubboCountCodec());// Dubbo业务处理器ch.pipeline().addLast("handler",newNettyServerHandler());}});ChannelFuturef=bootstrap.bind(getBindAddress());}}

四、Dubbo编解码器

// DubboCodec = 长度字段编解码 + Dubbo协议publicclassDubboCodecextendsExchangeCodec{protectedvoidencodeRequestData(Channelchannel,Objectoutput,ByteBufbuffer){// 序列化RPC调用数据：dubbo版本、服务名、方法名、参数等RpcInvocationinv=(RpcInvocation)output;ObjectOutputout=CodecSupport.getSerialization(channel.getUrl()).serialize(channel.getUrl(),buffer);out.writeUTF(inv.getAttachment(DUBBO_VERSION_KEY));out.writeUTF(inv.getAttachment(PATH_KEY));// 服务名out.writeUTF(inv.getAttachment(VERSION_KEY));out.writeUTF(inv.getMethodName());// 方法名out.writeUTF(inv.getParameterTypesDesc());// 参数类型// 写入参数值for(Objectarg:inv.getArguments()){out.writeObject(arg);}}}

五、Dubbo心跳机制

// 客户端发送心跳publicclassHeartbeatTimerTaskimplementsRunnable{publicvoidrun(){if(System.currentTimeMillis()-lastReadTime>heartbeat){// 发送心跳请求Requestreq=newRequest();req.setVersion(Version.getProtocolVersion());req.setTwoWay(true);req.setEvent(Request.HEARTBEAT_EVENT);channel.send(req);}}}// 服务端响应心跳if(request.isHeartbeat()){Responseresponse=newResponse();response.setEvent(Response.HEARTBEAT_EVENT);channel.send(response);return;}

六、总结

上一篇【第52篇】Netty秒杀系统——高并发网络接入层实战
下一篇【第54篇】Netty在Elasticsearch中的应用——分布式搜索引擎的网络通信