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.cloudgroupId>
<artifactId>spring-cloud-starter-gatewayartifactId>
<version>2.2.5.RELEASEversion>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-webfluxartifactId>
<version>2.3.2.RELEASEversion>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-reactor-nettyartifactId>
<version>2.3.2.RELEASEversion>
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
- 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
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;
@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();
}
@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);
}
}
六、参考源码
编程文档：
https://gitee.com/cicadasmile/butte-java-note
应用仓库：
https://gitee.com/cicadasmile/butte-flyer-parent
