如何利用SpringBoot、WebSocket和Netty实现高效的消息推送功能？请结合示例代码说明整个过程。

您好，以下是Spring Boot集成Netty实现WebSocket消息推送的示例代码： 1. 首先，在pom.xml文件中添加以下依赖： ``` <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-websocket</artifactId> </dependency> <dependency> <groupId>io.netty</groupId> <artifactId>netty-all</artifactId> <version>4.1.25.Final</version> </dependency> ``` 2. 创建WebSocket处理器类： ``` @Component @ChannelHandler.Sharable public class WebSocketHandler extends SimpleChannelInboundHandler<TextWebSocketFrame> { private static final Logger logger = LoggerFactory.getLogger(WebSocketHandler.class); private WebSocketServerHandshaker handshaker; @Override public void channelActive(ChannelHandlerContext ctx) throws Exception { logger.info("WebSocket连接已建立"); WebSocketManager.add(ctx.channel()); } @Override public void channelInactive(ChannelHandlerContext ctx) throws Exception { logger.info("WebSocket连接已关闭"); WebSocketManager.remove(ctx.channel()); } @Override protected void channelRead0(ChannelHandlerContext ctx, TextWebSocketFrame msg) throws Exception { logger.info("收到消息：" + msg.text()); // 处理消息 // ... } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { logger.error("WebSocket异常", cause); ctx.close(); } public void handleHttpRequest(ChannelHandlerContext ctx, FullHttpRequest req) { if (!req.decoderResult().isSuccess()) { sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HttpVersion.HTTP_1_1, HttpResponseStatus.BAD_REQUEST)); return; } WebSocketServerHandshakerFactory wsFactory = new WebSocketServerHandshakerFactory(getWebSocketLocation(req), null, true); handshaker = wsFactory.newHandshaker(req); if (handshaker == null) { WebSocketServerHandshakerFactory.sendUnsupportedVersionResponse(ctx.channel()); } else { handshaker.handshake(ctx.channel(), req); } } private static void sendHttpResponse(ChannelHandlerContext ctx, FullHttpRequest req, FullHttpResponse res) { if (res.status().code() != 200) { ByteBuf buf = Unpooled.copiedBuffer(res.status().toString(), CharsetUtil.UTF_8); res.content().writeBytes(buf); buf.release(); HttpUtil.setContentLength(res, res.content().readableBytes()); } ChannelFuture f = ctx.channel().writeAndFlush(res); if (!HttpUtil.isKeepAlive(req) || res.status().code() != 200) { f.addListener(ChannelFutureListener.CLOSE); } } private static String getWebSocketLocation(FullHttpRequest req) { String location = req.headers().get(HttpHeaderNames.HOST) + "/websocket"; return "ws://" + location; } } ``` 3. 创建WebSocket管理器类： ``` @Component public class WebSocketManager { private static final Logger logger = LoggerFactory.getLogger(WebSocketManager.class); private static final List<Channel> channels = new CopyOnWriteArrayList<>(); public static void add(Channel channel) { channels.add(channel); } public static void remove(Channel channel) { channels.remove(channel); } public static void broadcast(String message) { logger.info("广播消息：" + message); TextWebSocketFrame frame = new TextWebSocketFrame(message); for (Channel channel : channels) { if (channel.isActive()) { channel.writeAndFlush(frame); } } } } ``` 4. 创建WebSocket配置类： ``` @Configuration @EnableWebSocket public class WebSocketConfig implements WebSocketConfigurer { @Autowired private WebSocketHandler webSocketHandler; @Override public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) { registry.addHandler(webSocketHandler, "/websocket").setAllowedOrigins("*"); } } ``` 5. 在需要推送消息的地方调用WebSocketManager的broadcast方法即可： ``` WebSocketManager.broadcast("Hello, WebSocket!"); ``` 希望这个示例能够帮助到您。

以下是示例代码，仅供参考： ``` // 配置Netty服务器 @Configuration public class NettyConfig { @Value("${netty.port}") private int port; @Autowired private WebSocketHandler webSocketHandler; @Bean public EventLoopGroup bossGroup() { return new NioEventLoopGroup(); } @Bean public EventLoopGroup workerGroup() { return new NioEventLoopGroup(); } @Bean public ServerBootstrap serverBootstrap() { ServerBootstrap serverBootstrap = new ServerBootstrap(); serverBootstrap.group(bossGroup(), workerGroup()) .channel(NioServerSocketChannel.class) .option(ChannelOption.SO_BACKLOG, 128) .childOption(ChannelOption.SO_KEEPALIVE, true) .childHandler(new ChannelInitializer<SocketChannel>() { @Override protected void initChannel(SocketChannel ch) throws Exception { ChannelPipeline pipeline = ch.pipeline(); pipeline.addLast(new HttpServerCodec()); pipeline.addLast(new HttpObjectAggregator(65536)); pipeline.addLast(new WebSocketServerProtocolHandler("/ws")); pipeline.addLast(webSocketHandler); } }); return serverBootstrap; } @Bean public ChannelFuture nettyServer() { return serverBootstrap().bind(port); } } // WebSocket处理器 @Component public class WebSocketHandler extends TextWebSocketHandler { private static final Map<String, WebSocketSession> sessions = new ConcurrentHashMap<>(); @Override public void afterConnectionEstablished(WebSocketSession session) throws Exception { sessions.put(session.getId(), session); } @Override public void afterConnectionClosed(WebSocketSession session, CloseStatus status) throws Exception { sessions.remove(session.getId()); } @Override protected void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception { // 处理收到的消息 } public static void sendMessage(String sessionId, String message) throws IOException { WebSocketSession session = sessions.get(sessionId); if (session != null && session.isOpen()) { session.sendMessage(new TextMessage(message)); } } } ```