Netty是一個(gè)異步的，事件驅(qū)動(dòng)的網(wǎng)絡(luò)應(yīng)用框架，用以快速開發(fā)高可靠、高性能的網(wǎng)絡(luò)應(yīng)用程序。
一、Netty簡介
Netty是一個(gè)異步的，事件驅(qū)動(dòng)的網(wǎng)絡(luò)應(yīng)用框架，用以快速開發(fā)高可靠、高性能的網(wǎng)絡(luò)應(yīng)用程序。
傳輸服務(wù)：提供網(wǎng)絡(luò)傳輸能力的管理；
協(xié)議支持：支持常見的數(shù)據(jù)傳輸協(xié)議；
核心模塊：包括可擴(kuò)展事件模型、通用的通信API、零拷貝字節(jié)緩沖；
二、Netty入門案例
1、服務(wù)端啟動(dòng)
配置Netty服務(wù)器端程序，引導(dǎo)相關(guān)核心組件的加載；
public class NettyServer {
public static void main(String[] args) {
// EventLoop組，處理事件和IO
EventLoopGroup parentGroup = new NioEventLoopGroup();
EventLoopGroup childGroup = new NioEventLoopGroup();
try {
// 服務(wù)端啟動(dòng)引導(dǎo)類
ServerBootstrap serverBootstrap = new ServerBootstrap();
serverBootstrap.group(parentGroup, childGroup)
.channel(NioServerSocketChannel.class).childHandler(new ChannelInit());
// 異步IO的結(jié)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特殊的通道處理器，提供一種簡單的方法，對(duì)注冊(cè)到EventLoop的通道進(jìn)行初始化；比如此處設(shè)置的編碼解碼器，自定義處理器；
public class ChannelInit extends ChannelInitializer<SocketChannel> {
@Override
protected void initChannel(SocketChannel socketChannel) {
// 獲取管道
ChannelPipeline pipeline = socketChannel.pipeline();
// Http編碼、解碼器
pipeline.addLast("DefHttpServerCodec",new HttpServerCodec());
// 添加自定義的handler
pipeline.addLast("DefHttpHandler", new DefHandler());
}
}3、自定義處理器
處理對(duì)服務(wù)器端發(fā)起的訪問，通常包括請(qǐng)求解析，具體的邏輯執(zhí)行，請(qǐng)求響應(yīng)等過程；
public class DefHandler extends SimpleChannelInboundHandler<HttpObject> {
@Override
protected void channelRead0(ChannelHandlerContext ctx, HttpObject message) throws Exception {
if(message instanceof HttpRequest) {
// 請(qǐng)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()+"】");
}
// 響應(yīng)構(gòu)建
ByteBuf content = Unpooled.copiedBuffer("Netty服務(wù)", 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、測試請(qǐng)求
上面入門案例中，簡單的配置了一個(gè)Netty服務(wù)器端，啟動(dòng)之后在瀏覽器中模擬訪問即可；
http://127.0.0.1:8082/?id=1&name=Spring
三、Gateway集成
1、依賴層級(jí)
項(xiàng)目中Gateway網(wǎng)關(guān)依賴的版本為2.2.5.RELEASE?，發(fā)現(xiàn)Netty依賴的版本為4.1.45.Final，是當(dāng)下比較主流的版本；
<!-- 1、項(xiàng)目工程依賴 -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-gateway</artifactId>
<version>2.2.5.RELEASE</version>
</dependency>
<!-- 2、starter-gateway依賴 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-webflux</artifactId>
<version>2.3.2.RELEASE</version>
</dependency>
<!-- 3、starter-webflux依賴 -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-reactor-netty</artifactId>
<version>2.3.2.RELEASE</version>
</dependency>
2、自動(dòng)化配置
在Gateway網(wǎng)關(guān)的自動(dòng)化配置配置類中，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、配置加載
1、基礎(chǔ)配置
在工程的配置文件中，簡單做一些基礎(chǔ)性的設(shè)置；
server:
port: 8081 # 端口號(hào)
netty: # Netty組件
connection-timeout: 3000 # 連接超時(shí)
2、屬性配置類
在ServerProperties類中，并沒有提供很多顯式的Netty配置參數(shù)，更多信息需要參考工廠類；
@ConfigurationProperties(prefix = "server", ignoreUnknownFields = true)
public class ServerProperties {
private Integer port;
public static class Netty {
private Duration connectionTimeout;
}
}
3、配置加載分析
- 基于配置的屬性，定制化管理Netty服務(wù)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服務(wù)工廠，基于上述入門案例，創(chuàng)建WebServer時(shí)，部分參數(shù)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、控制類
Gateway項(xiàng)目中，Netty服務(wù)核心控制類，通過NettyReactiveWebServerFactory工廠類創(chuàng)建，對(duì)Netty生命周期的管理提供了一層包裝；
public class NettyWebServer implements WebServer {
private final HttpServer httpServer;
private final ReactorHttpHandlerAdapter handlerAdapter;
/**
* 啟動(dòng)方法
*/
@Override
public void start() throws WebServerException {
if (this.disposableServer == null) {
this.disposableServer = startHttpServer();
// 控制臺(tái)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) {
// 釋放資源
if (this.lifecycleTimeout != null) {
this.disposableServer.disposeNow(this.lifecycleTimeout);
}
else {
this.disposableServer.disposeNow();
}
// 對(duì)象銷毀
this.disposableServer = null;
}
}
}2、管理類
Netty組件中抽象管理類，以安全的方式構(gòu)建Http服務(wù)；
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、參考源碼
編程文檔：
https://gitee.com/cicadasmile/butte-java-note
應(yīng)用倉庫：
https://gitee.com/cicadasmile/butte-flyer-parent
