怎么集成netty（netty操作原理）

Gateway和Netty都有盲区的感觉；

一、Netty简介

Netty是一个异步的，事件驱动的网络应用框架，用以快速开发高可靠、高性能的网络应用程序。

怎么集成netty,netty操作原理(1)

传输服务：提供网络传输能力的管理；

协议支持：支持常见的数据传输协议；

核心模块：包括可扩展事件模型、通用的通信API、零拷贝字节缓冲；

二、Netty入门案例1、服务端启动

配置Netty服务器端程序，引导相关核心组件的加载；

public class NettyServer { public static void main(String[] args) { // EventLoop组，处理事件和IO EventLoopGroup parentGroup = new NioEventLoopGroup(); EventLoopGroup childGroup = new NioEventLoopGroup(); try { // 服务端启动引导类 ServerBootstrap serverBootstrap = new ServerBootstrap(); serverBootstrap.group(parentGroup, childGroup) .channel(NioserverSocketChannel.class).childhandler(new ChannelInit()); // 异步IO的结果 ChannelFuture channelFuture = serverBootstrap.bind(8082).sync(); channelFuture.channel().closeFuture().sync(); } catch (Exception e){ e.printStackTrace(); } finally { parentGroup.shutdownGracefully(); childGroup.shutdownGracefully(); } } }2、通道初始化

ChannelInitializer特殊的通道处理器，提供一种简单的方法，对注册到EventLoop的通道进行初始化；比如此处设置的编码解码器，自定义处理器；

public class ChannelInit extends ChannelInitializer<SocketChannel> { @Override protected void initChannel(SocketChannel socketChannel) { // 获取管道 ChannelPipeline pipeline = socketChannel.pipeline(); // Http编码、解码器 pipeline.addLast("DefHttpServerCodec",new HttpServerCodec()); // 添加自定义的handler pipeline.addLast("DefHttpHandler", new DefHandler()); } }3、自定义处理器

处理对服务器端发起的访问，通常包括请求解析，具体的逻辑执行，请求响应等过程；

public class DefHandler extends SimpleChannelInboundHandler<HttpObject> { @Override protected void channelRead0(ChannelHandlerContext ctx, HttpObject message) throws Exception { if(message instanceof HttpRequest) { // 请求解析 HttpRequest httpRequest = (HttpRequest) message; String uri = httpRequest.uri(); String method = httpRequest.method().name(); log.info("【HttpRequest-URI:" uri "】"); log.info("【HttpRequest-method:" method "】"); iterator<Map.Entry<String,String>> iterator = httpRequest.headers().iteratorAsString(); while (iterator.hasNext()){ Map.Entry<String,String> entry = iterator.next(); log.info("【Header-Key:" entry.getKey() ";Header-Value:" entry.getValue() "】"); } // 响应构建 ByteBuf content = Unpooled.copiedBuffer("Netty服务", charsetUtil.UTF_8); FullHttpResponse response = new DefaultFullHttpResponse (HttpVersion.HTTP_1_1, HttpResponseStatus.OK, content); response.headers().set(HttpHeaderNames.CONTENT_TYPE, "text/plain;charset=utf-8"); response.headers().set(HttpHeaderNames.CONTENT_LENGTH, content.readableBytes()); ctx.writeAndFlush(response); } } }4、测试请求

上面入门案例中，简单的配置了一个Netty服务器端，启动之后在浏览器中模拟访问即可；

http://127.0.0.1:8082/?id=1&name=Spring三、Gateway集成1、依赖层级

项目中Gateway网关依赖的版本为2.2.5.RELEASE，发现Netty依赖的版本为4.1.45.Final，是当下比较主流的版本；

<dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-gateway</artifactId> <version>2.2.5.RELEASE</version> </dependency>  <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-webflux</artifactId> <version>2.3.2.RELEASE</version> </dependency>  <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-reactor-netty</artifactId> <version>2.3.2.RELEASE</version> </dependency>2、自动化配置

在Gateway网关的自动化配置配置类中，提供了Netty配置的管理；

@AutoConfigureBefore({ HttpHandlerAutoConfiguration.class,WebFluxAutoConfiguration.class }) @ConditionalOnClass(DispatcherHandler.class) public class GatewayAutoConfiguration { @Configuration(proxyBeanMethods = false) @ConditionalOnClass(HttpClient.class) protected static class NettyConfiguration { @Bean @ConditionalOnProperty(name = "spring.cloud.gateway.httpserver.wiretap") public NettyWebServerFactoryCustomizer nettyServerWiretapCustomizer( Environment environment, ServerProperties serverProperties) { return new NettyWebServerFactoryCustomizer(environment, serverProperties) { @Override public void customize(NettyReactiveWebServerFactory factory) { factory.addServerCustomizers(httpServer -> httpServer.wiretap(true)); super.customize(factory); } }; } } }四、配置加载1、基础配置

在工程的配置文件中，简单做一些基础性的设置；

server: port: 8081 # 端口号 netty: # Netty组件 connection-timeout: 3000 # 连接超时2、属性配置类

在ServerProperties类中，并没有提供很多显式的Netty配置参数，更多信息需要参考工厂类；

@ConfigurationProperties(prefix = "server", ignoreUnknownFields = true) public class ServerProperties { private Integer port; public static class Netty { private Duration connectionTimeout; } }3、配置加载分析

怎么集成netty,netty操作原理(2)

基于配置的属性，定制化管理Netty服务的信息；

public class NettyWebServerFactoryCustomizer implements WebServerFactoryCustomizer<NettyReactiveWebServerFactory>{ private final Environment environment; private final ServerProperties serverProperties; @Override public void customize(NettyReactiveWebServerFactory factory) { PropertyMapper propertyMapper = PropertyMapper.get().alwaysApplyingWhenNonNull(); ServerProperties.Netty nettyProperties = this.serverProperties.getNetty(); propertyMapper.from(nettyProperties::getConnectionTimeout).whenNonNull() .to((connectionTimeout) -> customizeConnectionTimeout(factory, connectionTimeout)); } }

NettyReactiveWeb服务工厂，基于上述入门案例，创建WebServer时，部分参数信息出自LoopResources接口；

public class NettyReactiveWebServerFactory extends AbstractReactiveWebServerFactory { private ReactorResourceFactory resourceFactory; @Override public WebServer getWebServer(HttpHandler httpHandler) { HttpServer httpServer = createHttpServer(); ReactorHttpHandlerAdapter handlerAdapter = new ReactorHttpHandlerAdapter(httpHandler); NettyWebServer webServer = new NettyWebServer(httpServer, handlerAdapter, this.lifecycleTimeout); webServer.setRouteProviders(this.routeProviders); return webServer; } private HttpServer createHttpServer() { HttpServer server = HttpServer.create(); if (this.resourceFactory != null) { LoopResources resources = this.resourceFactory.getLoopResources(); server = server.tcpConfiguration( (tcpServer) -> tcpServer.runOn(resources).addressSupplier(this::getListenAddress)); } return applyCustomizers(server); } }五、周期管理方法1、控制类

怎么集成netty,netty操作原理(3)

Gateway项目中，Netty服务核心控制类，通过NettyReactiveWebServerFactory工厂类创建，对Netty生命周期的管理提供了一层包装；

public class NettyWebServer implements WebServer { private final HttpServer httpServer; private final ReactorHttpHandlerAdapter handlerAdapter; /** * 启动方法 */ @Override public void start() throws WebServerException { if (this.disposableServer == null) { this.disposableServer = startHttpServer(); // 控制台日志 logger.info("Netty started on port(s): " getPort()); startDaemonAwaitThread(this.disposableServer); } } private DisposableServer startHttpServer() { HttpServer server = this.httpServer; if (this.routeProviders.isEmpty()) { server = server.handle(this.handlerAdapter); } return server.bindNow(); } /** * 停止方法 */ @Override public void stop() throws WebServerException { if (this.disposableServer != null) { // 释放资源 if (this.lifecycleTimeout != null) { this.disposableServer.disposeNow(this.lifecycleTimeout); } else { this.disposableServer.disposeNow(); } // 对象销毁 this.disposableServer = null; } } }2、管理类

Netty组件中抽象管理类，以安全的方式构建Http服务；

public abstract class HttpServer { public static HttpServer create() { return HttpServerBind.INSTANCE; } public final DisposableServer bindNow() { return bindNow(Duration.ofSeconds(45)); } public final HttpServer handle(BiFunction<? super HttpServerRequest, ? super HttpServerResponse, ? extends Publisher<Void>> handler) { return new HttpServerHandle(this, handler); } }

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怎么集成netty,netty操作原理(4)