netty-socketio 概述
netty-socketio是一个开源的Socket.io服务器端的一个java的实现，它基于Netty框架，可用于服务端推送消息给客户端。
说到服务端推送技术，一般会涉及WebSocket，WebSocket是HTML5最新提出的规范，虽然主流浏览器都已经支持，但仍然可能有不兼容的情况，为了兼容所有浏览器，给程序员提供一致的编程体验，SocketIO将WebSocket、AJAX和其它的通信方式全部封装成了统一的通信接口，也就是说，使用SocketIO时不用担心兼容问题，底层会自动选用最佳的通信方式。
netty-socketio 框架事件流程
netty-socketio 示例demo
pom.xml
1<dependencies> 2 <dependency> 3 <groupId>org.springframework.boot</groupId> 4 <artifactId>spring-boot-starter-web</artifactId> 5 </dependency> 6 <dependency> 7 <groupId>com.corundumstudio.socketio</groupId> 8 <artifactId>netty-socketio</artifactId> 9 <version>1.7.17</version> 10 </dependency> 11 <dependency> 12 <groupId>org.projectlombok</groupId> 13 <artifactId>lombok</artifactId> 14 <version>1.18.4</version> 15 <scope>provided</scope> 16 </dependency> 17 18</dependencies>
启动类 NettySocketioApplication
1@SpringBootApplication 2@Slf4j 3public class NettySocketioApplication implements CommandLineRunner { 4 5 public static void main(String[] args) { 6 SpringApplication.run(NettySocketioApplication.class, args); 7 } 8 9 @Autowired 10 private SocketIOServer socketIOServer; 11 12 @Override 13 public void run(String... strings) { 14 socketIOServer.start(); 15 log.info("socket.io启动成功！"); 16 } 17}
Message
1@Data 2public class Message { 3 4 private String msg; 5}
配置类 NettySocketioConfig
1@Configuration 2public class NettySocketioConfig { 3 /** 4 * netty-socketio服务器 5 */ 6 @Bean 7 public SocketIOServer socketIOServer() { 8 com.corundumstudio.socketio.Configuration config = new com.corundumstudio.socketio.Configuration(); 9 config.setHostname("localhost"); 10 config.setPort(9092); 11 12 SocketIOServer server = new SocketIOServer(config); 13 return server; 14 } 15 16 /** 17 * 用于扫描netty-socketio的注解，比如 @OnConnect、@OnEvent 18 */ 19 @Bean 20 public SpringAnnotationScanner springAnnotationScanner() { 21 return new SpringAnnotationScanner(socketIOServer()); 22 } 23}
消息处理器 MessageEventHandler
1@Component 2@Slf4j 3public class MessageEventHandler { 4 5 @Autowired 6 private SocketIOServer socketIoServer; 7 8 public static ConcurrentMap<String, SocketIOClient> socketIOClientMap = new ConcurrentHashMap<>(); 9 10 /** 11 * 客户端连接的时候触发 12 * 13 * @param client 14 */ 15 @OnConnect 16 public void onConnect(SocketIOClient client) { 17 String mac = client.getHandshakeData().getSingleUrlParam("mac"); 18 //存储SocketIOClient，用于发送消息 19 socketIOClientMap.put(mac, client); 20 //回发消息 21 client.sendEvent("message", "onConnect back"); 22 log.info("客户端:" + client.getSessionId() + "已连接,mac=" + mac); 23 } 24 25 /** 26 * 客户端关闭连接时触发 27 * 28 * @param client 29 */ 30 @OnDisconnect 31 public void onDisconnect(SocketIOClient client) { 32 log.info("客户端:" + client.getSessionId() + "断开连接"); 33 } 34 35 /** 36 * 客户端事件 37 * 38 * @param client 客户端信息 39 * @param request 请求信息 40 * @param data 客户端发送数据 41 */ 42 @OnEvent(value = "messageevent") 43 public void onEvent(SocketIOClient client, AckRequest request, Message data) { 44 log.info("发来消息：" + data); 45 //回发消息 46 client.sendEvent("messageevent", "我是服务器都安发送的信息"); 47 //广播消息 48 sendBroadcast(); 49 } 50 51 /** 52 * 广播消息 53 */ 54 public void sendBroadcast() { 55 for (SocketIOClient client : socketIOClientMap.values()) { 56 if (client.isChannelOpen()) { 57 client.sendEvent("Broadcast", "当前时间", System.currentTimeMillis()); 58 } 59 } 60 61 } 62}
html 页面
1<!doctype html> 2<html lang="en"> 3<head> 4 <meta charset="UTF-8"> 5 <meta name="viewport" content="width=device-width,initial-scale=1, maximum-scale=1, user-scalable=no"> 6 <title>websocket-java-socketio</title> 7 <script src="https://cdn.bootcss.com/socket.io/2.2.0/socket.io.js"></script> 8</head> 9<body> 10<h1>Socket.io Test</h1> 11<div><p id="status">Waiting for input</p></div> 12<div><p id="message">hello world!</p></div> 13<button id="connect" onClick='connect()'/>Connect</button> 14<button id="disconnect" onClick='disconnect()'>Disconnect</button> 15<button id="send" onClick='send()'/>Send Message</button> 16</body> 17 18<script type="text/javascript"> 19 20 /** 21 * 前端js的 socket.emit("事件名","参数数据")方法，是触发后端自定义消息事件的时候使用的, 22 * 前端js的 socket.on("事件名",匿名函数(服务器向客户端发送的数据))为监听服务器端的事件 23 **/ 24 var socket = io.connect("http://localhost:9092?mac=2"); 25 var firstconnect = true; 26 27 function connect() { 28 if(firstconnect) { 29 30 //socket.on('reconnect', function(){ status_update("Reconnected to Server"); }); 31 //socket.on('reconnecting', function( nextRetry ){ status_update("Reconnecting in " 32 //+ nextRetry + " seconds"); }); 33 //socket.on('reconnect_failed', function(){ message("Reconnect Failed"); }); 34 //firstconnect = false; 35 } else { 36 socket.socket.reconnect(); 37 } 38 } 39 40 //监听服务器连接事件 41 socket.on('connect', function(){ status_update("Connected to Server"); }); 42 //监听服务器关闭服务事件 43 socket.on('disconnect', function(){ status_update("Disconnected from Server"); }); 44 //监听服务器端发送消息事件 45 socket.on('messageevent', function(data) { 46 message(data) 47 //console.log("服务器发送的消息是："+data); 48 }); 49 50 //断开连接 51 function disconnect() { 52 socket.disconnect(); 53 } 54 55 function message(data) { 56 document.getElementById('message').innerHTML = "Server says: " + data; 57 } 58 59 function status_update(txt){ 60 document.getElementById('status').innerHTML = txt; 61 } 62 63 function esc(msg){ 64 return msg.replace(/</g, '<').replace(/>/g, '>'); 65 } 66 //点击发送消息触发 67 function send() { 68 console.log("点击了发送消息，开始向服务器发送消息") 69 var msg = "我很好的,是的．"; 70 socket.emit('messageevent', {msgContent: msg}); 71 }; 72</script> 73</html>
执行输出
运行 SpringBoot 服务器
> mvn spring-boot:run
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