Spring Boot + Netty + WebSocket 实现消息推送

1、关于Netty

Netty 是一个利用 Java 的高级网络的能力，隐藏其背后的复杂性而提供一个易于使用的 API 的客户端/服务器框架。

2、Maven依赖

<dependencies><!-- https://mvnrepository.com/artifact/io.netty/netty-all --><dependency><groupId>io.netty</groupId><artifactId>netty-all</artifactId><version>4.1.36.Final</version></dependency>
</dependencies>

3、SpringBootApplication

启动器中需要new一个NettyServer，并显式调用启动netty。

@SpringBootApplication
public class SpringCloudStudyDemoApplication {public static void main(String[] args) {SpringApplication.run(SpringCloudStudyDemoApplication.class,args);try {new NettyServer(12345).start();System.out.println("https://blog.csdn.net/moshowgame");System.out.println("http://127.0.0.1:6688/netty-websocket/index");}catch(Exception e) {System.out.println("NettyServerError:"+e.getMessage());}}
}

4、NettyServer

启动的NettyServer，这里进行配置

/*** NettyServer Netty服务器配置*/
public class NettyServer {private final int port;public NettyServer(int port) {this.port = port;}public void start() throws Exception {EventLoopGroup bossGroup = new NioEventLoopGroup();EventLoopGroup group = new NioEventLoopGroup();try {ServerBootstrap sb = new ServerBootstrap();sb.option(ChannelOption.SO_BACKLOG, 1024);sb.group(group, bossGroup) // 绑定线程池.channel(NioServerSocketChannel.class) // 指定使用的channel.localAddress(this.port)// 绑定监听端口.childHandler(new ChannelInitializer<SocketChannel>() { // 绑定客户端连接时候触发操作@Overrideprotected void initChannel(SocketChannel ch) throws Exception {System.out.println("收到新连接");//websocket协议本身是基于http协议的，所以这边也要使用http解编码器ch.pipeline().addLast(new HttpServerCodec());//以块的方式来写的处理器ch.pipeline().addLast(new ChunkedWriteHandler());ch.pipeline().addLast(new HttpObjectAggregator(8192));ch.pipeline().addLast(new WebSocketServerProtocolHandler("/ws", null, true, 65536 * 10));ch.pipeline().addLast(new MyWebSocketHandler());}});ChannelFuture cf = sb.bind().sync(); // 服务器异步创建绑定System.out.println(NettyServer.class + " 启动正在监听：" + cf.channel().localAddress());cf.channel().closeFuture().sync(); // 关闭服务器通道} finally {group.shutdownGracefully().sync(); // 释放线程池资源bossGroup.shutdownGracefully().sync();}}
}

5、MyChannelHandlerPool

通道组池，管理所有websocket连接

/*** MyChannelHandlerPool* 通道组池，管理所有websocket连接*/
public class MyChannelHandlerPool {public MyChannelHandlerPool(){}public static ChannelGroup channelGroup = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
}

6、MyWebSocketHandler

处理ws一下几种情况：

channelActive与客户端建立连接
channelInactive与客户端断开连接
channelRead0客户端发送消息处理

/*** NettyServer Netty服务器配置*/
public class NettyServer {private final int port;public NettyServer(int port) {this.port = port;}public void start() throws Exception {EventLoopGroup bossGroup = new NioEventLoopGroup();EventLoopGroup group = new NioEventLoopGroup();try {ServerBootstrap sb = new ServerBootstrap();sb.option(ChannelOption.SO_BACKLOG, 1024);sb.group(group, bossGroup) // 绑定线程池.channel(NioServerSocketChannel.class) // 指定使用的channel.localAddress(this.port)// 绑定监听端口.childHandler(new ChannelInitializer<SocketChannel>() { // 绑定客户端连接时候触发操作@Overrideprotected void initChannel(SocketChannel ch) throws Exception {System.out.println("收到新连接");//websocket协议本身是基于http协议的，所以这边也要使用http解编码器ch.pipeline().addLast(new HttpServerCodec());//以块的方式来写的处理器ch.pipeline().addLast(new ChunkedWriteHandler());ch.pipeline().addLast(new HttpObjectAggregator(8192));ch.pipeline().addLast(new WebSocketServerProtocolHandler("/ws", "WebSocket", true, 65536 * 10));ch.pipeline().addLast(new MyWebSocketHandler());}});ChannelFuture cf = sb.bind().sync(); // 服务器异步创建绑定System.out.println(NettyServer.class + " 启动正在监听：" + cf.channel().localAddress());cf.channel().closeFuture().sync(); // 关闭服务器通道} finally {group.shutdownGracefully().sync(); // 释放线程池资源bossGroup.shutdownGracefully().sync();}}
}

7、socket.html

主要是连接ws，发送消息，以及消息反馈

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head><meta http-equiv="Content-Type" content="text/html; charset=utf-8" /><title>Netty-Websocket</title><script type="text/javascript">// by zhengkai.blog.csdn.netvar socket;if(!window.WebSocket){window.WebSocket = window.MozWebSocket;}if(window.WebSocket){socket = new WebSocket("ws://127.0.0.1:12345/ws");socket.onmessage = function(event){var ta = document.getElementById('responseText');ta.value += event.data+"\r\n";};socket.onopen = function(event){var ta = document.getElementById('responseText');ta.value = "Netty-WebSocket服务器。。。。。。连接 \r\n";};socket.onclose = function(event){var ta = document.getElementById('responseText');ta.value = "Netty-WebSocket服务器。。。。。。关闭 \r\n";};}else{alert("您的浏览器不支持WebSocket协议！");}function send(message){if(!window.WebSocket){return;}if(socket.readyState == WebSocket.OPEN){socket.send(message);}else{alert("WebSocket 连接没有建立成功！");}}</script>
</head>
<body>
<form onSubmit="return false;"><label>ID</label><input type="text" name="uid" value="${uid!!}" /> <br /><label>TEXT</label><input type="text" name="message" value="这里输入消息" /> <br /><br /> <input type="button" value="发送ws消息"onClick="send(this.form.uid.value+':'+this.form.message.value)" /><hr color="black" /><h3>服务端返回的应答消息</h3><textarea id="responseText" style="width: 1024px;height: 300px;"></textarea>
</form>
</body>
</html>

8、Controller

写好了html当然还需要一个controller来引导页面。

@RestController
public class IndexController {@GetMapping("/index")public ModelAndView index(){ModelAndView mav=new ModelAndView("socket");mav.addObject("uid", RandomUtil.randomNumbers(6));return mav;}
}

9、改造netty支持url参数

1.首先，调整一下加载handler的顺序，优先MyWebSocketHandler在WebSocketServerProtocolHandler之上。

ch.pipeline().addLast(new MyWebSocketHandler());
ch.pipeline().addLast(new WebSocketServerProtocolHandler("/ws", null, true, 65536 * 10));

2.其次，改造MyWebSocketHandler 的channelRead方法，首次连接会是一个FullHttpRequest类型，可以通过FullHttpRequest.uri()获取完整ws的URL地址，之后接受信息的话，会是一个TextWebSocketFrame类型。

public class MyWebSocketHandler extends SimpleChannelInboundHandler<TextWebSocketFrame> {@Overridepublic void channelActive(ChannelHandlerContext ctx) throws Exception {System.out.println("与客户端建立连接，通道开启！");//添加到channelGroup通道组MyChannelHandlerPool.channelGroup.add(ctx.channel());}@Overridepublic void channelInactive(ChannelHandlerContext ctx) throws Exception {System.out.println("与客户端断开连接，通道关闭！");//添加到channelGroup 通道组MyChannelHandlerPool.channelGroup.remove(ctx.channel());}@Overridepublic void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {//首次连接是FullHttpRequest，处理参数 by zhengkai.blog.csdn.netif (null != msg && msg instanceof FullHttpRequest) {FullHttpRequest request = (FullHttpRequest) msg;String uri = request.uri();Map paramMap=getUrlParams(uri);System.out.println("接收到的参数是："+JSON.toJSONString(paramMap));//如果url包含参数，需要处理if(uri.contains("?")){String newUri=uri.substring(0,uri.indexOf("?"));System.out.println(newUri);request.setUri(newUri);}}else if(msg instanceof TextWebSocketFrame){//正常的TEXT消息类型TextWebSocketFrame frame=(TextWebSocketFrame)msg;System.out.println("客户端收到服务器数据：" +frame.text());sendAllMessage(frame.text());}super.channelRead(ctx, msg);}@Overrideprotected void channelRead0(ChannelHandlerContext channelHandlerContext, TextWebSocketFrame textWebSocketFrame) throws Exception {}private void sendAllMessage(String message){//收到信息后，群发给所有channelMyChannelHandlerPool.channelGroup.writeAndFlush( new TextWebSocketFrame(message));}private static Map getUrlParams(String url){Map<String,String> map = new HashMap<>();url = url.replace("?",";");if (!url.contains(";")){return map;}if (url.split(";").length > 0){String[] arr = url.split(";")[1].split("&");for (String s : arr){String key = s.split("=")[0];String value = s.split("=")[1];map.put(key,value);}return  map;}else{return map;}}
}

3.html中的ws地址也进行改造

socket = new WebSocket("ws://127.0.0.1:12345/ws?uid=666&gid=777");

4.改造后控制台输出情况

收到新连接
与客户端建立连接，通道开启！
接收到的参数是：{"uid":"666","gid":"777"}
/ws
客户端收到服务器数据：142531:这里输入消息
客户端收到服务器数据：142531:这里输入消息
客户端收到服务器数据：142531:这里输入消息

failed: WebSocket opening handshake timed out