Netty是一个非常优秀的Socket框架。如果需要在SpringBoot开发的app中,提供Socket服务,那么Netty是不错的选择。
Netty与SpringBoot的整合,我想无非就是要整合几个地方
- 让netty跟springboot生命周期保持一致,同生共死
- 让netty能用上ioc中的Bean
- 让netty能读取到全局的配置
整合Netty,提供WebSocket服务
这里演示一个案例,在SpringBoot中使用Netty提供一个Websocket服务。
servlet容器本身提供了websocket的实现,但这里用netty的实现 :sparkling_heart:
添加依赖
<dependency><groupId>io.netty</groupId><artifactId>netty-all</artifactId>
</dependency>
是的,不用声明版本号。因为 spring-boot-dependencies 中已经声明了最新的netty依赖。
通过yaml配置基本的属性
server:port: 80logging:level:root: DEBUGmanagement:endpoints: web:exposure:include: "*"endpoint:shutdown:enabled: truenetty:websocket:# Websocket服务端口port: 1024# 绑定的网卡ip: 0.0.0.0# 消息帧最大体积max-frame-size: 10240# URI路径path: /channel
App使用了,actuator,并且开启暴露了 shutdown
端点,可以让SpringBoot App优雅的停机。 在这里通过 netty.websocket.*
配置 websocket服务相关的配置。
通过 ApplicationRunner 启动Websocket服务
import java.net.InetSocketAddress;import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.ApplicationListener;
import org.springframework.context.event.ContextClosedEvent;
import org.springframework.stereotype.Component;import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.http.DefaultFullHttpResponse;
import io.netty.handler.codec.http.FullHttpRequest;
import io.netty.handler.codec.http.HttpObjectAggregator;
import io.netty.handler.codec.http.HttpResponseStatus;
import io.netty.handler.codec.http.HttpServerCodec;
import io.netty.handler.codec.http.HttpVersion;
import io.netty.handler.codec.http.websocketx.WebSocketServerProtocolHandler;
import io.netty.handler.codec.http.websocketx.extensions.compression.WebSocketServerCompressionHandler;
import io.netty.handler.stream.ChunkedWriteHandler;
import io.springboot.netty.websocket.handler.WebsocketMessageHandler;/*** 初始化Netty服务* @author Administrator*/
@Component
public class NettyBootsrapRunner implements ApplicationRunner, ApplicationListener<ContextClosedEvent>, ApplicationContextAware {private static final Logger LOGGER = LoggerFactory.getLogger(NettyBootsrapRunner.class);@Value("${netty.websocket.port}")private int port;@Value("${netty.websocket.ip}")private String ip;@Value("${netty.websocket.path}")private String path;@Value("${netty.websocket.max-frame-size}")private long maxFrameSize;private ApplicationContext applicationContext;private Channel serverChannel;public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {this.applicationContext = applicationContext;}public void run(ApplicationArguments args) throws Exception {EventLoopGroup bossGroup = new NioEventLoopGroup();EventLoopGroup workerGroup = new NioEventLoopGroup();try {ServerBootstrap serverBootstrap = new ServerBootstrap();serverBootstrap.group(bossGroup, workerGroup);serverBootstrap.channel(NioServerSocketChannel.class);serverBootstrap.localAddress(new InetSocketAddress(this.ip, this.port));serverBootstrap.childHandler(new ChannelInitializer<SocketChannel>() {@Overrideprotected void initChannel(SocketChannel socketChannel) throws Exception {ChannelPipeline pipeline = socketChannel.pipeline();pipeline.addLast(new HttpServerCodec());pipeline.addLast(new ChunkedWriteHandler());pipeline.addLast(new HttpObjectAggregator(65536));pipeline.addLast(new ChannelInboundHandlerAdapter() {@Overridepublic void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {if(msg instanceof FullHttpRequest) {FullHttpRequest fullHttpRequest = (FullHttpRequest) msg;String uri = fullHttpRequest.uri();if (!uri.equals(path)) {// 访问的路径不是 websocket的端点地址,响应404ctx.channel().writeAndFlush(new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.NOT_FOUND)).addListener(ChannelFutureListener.CLOSE);return ;}}super.channelRead(ctx, msg);}});pipeline.addLast(new WebSocketServerCompressionHandler());pipeline.addLast(new WebSocketServerProtocolHandler(path, null, true, maxFrameSize));/*** 从IOC中获取到Handler*/pipeline.addLast(applicationContext.getBean(WebsocketMessageHandler.class));}});Channel channel = serverBootstrap.bind().sync().channel(); this.serverChannel = channel;LOGGER.info("websocket 服务启动,ip={},port={}", this.ip, this.port);channel.closeFuture().sync();} finally {bossGroup.shutdownGracefully();workerGroup.shutdownGracefully();}}public void onApplicationEvent(ContextClosedEvent event) {if (this.serverChannel != null) {this.serverChannel.close();}LOGGER.info("websocket 服务停止");}
}
NettyBootsrapRunner
实现了 ApplicationRunner, ApplicationListener<ContextClosedEvent>
, ApplicationContextAware
接口。
这样一来,NettyBootsrapRunner
可以在App的启动和关闭时执行Websocket服务的启动和关闭。而且通过 ApplicationContextAware
还能获取到 ApplicationContext
通过IOC管理 Netty 的Handler
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandler.Sharable;
import io.netty.handler.codec.http.websocketx.TextWebSocketFrame;
import io.netty.handler.codec.http.websocketx.WebSocketCloseStatus;
import io.netty.handler.codec.http.websocketx.WebSocketFrame;
import io.springboot.netty.service.DiscardService;
/*** * @author Administrator**/
@Sharable
@Component
public class WebsocketMessageHandler extends SimpleChannelInboundHandler<WebSocketFrame> {private static final Logger LOGGER = LoggerFactory.getLogger(WebsocketMessageHandler.class);@AutowiredDiscardService discardService;@Overrideprotected void channelRead0(ChannelHandlerContext ctx, WebSocketFrame msg) throws Exception {if (msg instanceof TextWebSocketFrame) {TextWebSocketFrame textWebSocketFrame = (TextWebSocketFrame) msg;// 业务层处理数据this.discardService.discard(textWebSocketFrame.text());// 响应客户端ctx.channel().writeAndFlush(new TextWebSocketFrame("我收到了你的消息:" + System.currentTimeMillis()));} else {// 不接受文本以外的数据帧类型ctx.channel().writeAndFlush(WebSocketCloseStatus.INVALID_MESSAGE_TYPE).addListener(ChannelFutureListener.CLOSE);}}@Overridepublic void channelInactive(ChannelHandlerContext ctx) throws Exception {super.channelInactive(ctx);LOGGER.info("链接断开:{}", ctx.channel().remoteAddress());}@Overridepublic void channelActive(ChannelHandlerContext ctx) throws Exception {super.channelActive(ctx);LOGGER.info("链接创建:{}", ctx.channel().remoteAddress());}
}
handler已经是一个IOC管理的Bean,可以自由的使用依赖注入等Spring带来的快捷功能。由于是单例存在,所有的链接都使用同一个hander,所以尽量不要保存任何实例变量。
这个Handler处理完毕客户端的消息后,给客户端会响应一条:"我收到了你的消息:" + System.currentTimeMillis()
的消息
为了演示在Handler中使用业务层,这里假装注入了一个 DiscardService
服务。它的逻辑很简单,就是丢弃消息
public void discard (String message) {LOGGER.info("丢弃消息:{}", message);
}
演示
启动客户端
<!DOCTYPE html><html><head><meta charset="UTF-8"><title>Websocket</title></head><body></body><script type="text/javascript">;(function(){const websocket = new WebSocket('ws://localhost:1024/channel');websocket.onmessage = e => {console.log('收到消息:', e.data);}websocket.onclose = e => {let {code, reason} = e;console.log(`链接断开:code=${code}, reason=${reason}`);}websocket.onopen = () => {console.log(`链接建立...`);websocket.send('Hello');}websocket.onerror = e => {console.log('链接异常:', e);}})();</script>
</html>
链接创建后就给服务端发送一条消息:Hello
关闭服务端
使用 PostMan 请求服务器的停机端点
日志
客户端日志
服务端日志
2020-06-22 17:08:22.728 INFO 9392 --- [ main] io.undertow : starting server: Undertow - 2.1.3.Final
2020-06-22 17:08:22.740 INFO 9392 --- [ main] org.xnio : XNIO version 3.8.0.Final
2020-06-22 17:08:22.752 INFO 9392 --- [ main] org.xnio.nio : XNIO NIO Implementation Version 3.8.0.Final
2020-06-22 17:08:22.839 INFO 9392 --- [ main] org.jboss.threads : JBoss Threads version 3.1.0.Final
2020-06-22 17:08:22.913 INFO 9392 --- [ main] o.s.b.w.e.undertow.UndertowWebServer : Undertow started on port(s) 80 (http)
2020-06-22 17:08:22.931 INFO 9392 --- [ main] io.springboot.netty.NettyApplication : Started NettyApplication in 4.536 seconds (JVM running for 5.175)
2020-06-22 17:08:23.653 INFO 9392 --- [ main] i.s.n.w.runner.NettyBootsrapRunner : websocket 服务启动,ip=0.0.0.0,port=1024
2020-06-22 17:08:28.484 INFO 9392 --- [ XNIO-1 task-1] io.undertow.servlet : Initializing Spring DispatcherServlet 'dispatcherServlet'
2020-06-22 17:08:28.484 INFO 9392 --- [ XNIO-1 task-1] o.s.web.servlet.DispatcherServlet : Initializing Servlet 'dispatcherServlet'
2020-06-22 17:08:28.492 INFO 9392 --- [ XNIO-1 task-1] o.s.web.servlet.DispatcherServlet : Completed initialization in 8 ms
2020-06-22 17:08:28.724 INFO 9392 --- [ntLoopGroup-3-1] i.s.n.w.handler.WebsocketMessageHandler : 链接创建:/0:0:0:0:0:0:0:1:12093
2020-06-22 17:08:28.790 INFO 9392 --- [ntLoopGroup-3-1] i.s.netty.service.DiscardService : 丢弃消息:Hello
2020-06-22 17:08:33.688 INFO 9392 --- [ Thread-232] i.s.n.w.runner.NettyBootsrapRunner : websocket 服务停止
2020-06-22 17:08:33.691 INFO 9392 --- [ntLoopGroup-3-1] i.s.n.w.handler.WebsocketMessageHandler : 链接断开:/0:0:0:0:0:0:0:1:12093
2020-06-22 17:08:33.699 INFO 9392 --- [ Thread-232] io.undertow : stopping server: Undertow - 2.1.3.Final
2020-06-22 17:08:33.704 INFO 9392 --- [ Thread-232] io.undertow.servlet : Destroying Spring FrameworkServlet 'dispatcherServlet'
2020-06-22 17:08:33.708 INFO 9392 --- [ Thread-232] o.s.s.concurrent.ThreadPoolTaskExecutor : Shutting down ExecutorService 'applicationTaskExecutor'
复制代码
Netty会在SpringBoot App启动后启动,App停止后关闭,可以正常的对外提供服务 并且Handler交给IOC管理可以注入Service,完成业务处理。