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。
pom.xml
<dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>com.corundumstudio.socketio</groupId> <artifactId>netty-socketio</artifactId> <version>1.7.17</version> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <version>1.18.4</version> <scope>provided</scope> </dependency> </dependencies>启动类 NettySocketioApplication
@SpringBootApplication @Slf4j public class NettySocketioApplication implements CommandLineRunner { public static void main(String[] args) { SpringApplication.run(NettySocketioApplication.class, args); } @Autowired private SocketIOServer socketIOServer; @Override public void run(String... strings) { socketIOServer.start(); log.info("socket.io启动成功！"); } }Message
@Data public class Message { private String msg; }配置类 NettySocketioConfig
@Configuration public class NettySocketioConfig { /** * netty-socketio服务器 */ @Bean public SocketIOServer socketIOServer() { com.corundumstudio.socketio.Configuration config = new com.corundumstudio.socketio.Configuration(); config.setHostname("localhost"); config.setPort(9092); SocketIOServer server = new SocketIOServer(config); return server; } /** * 用于扫描netty-socketio的注解，比如 @OnConnect、@OnEvent */ @Bean public SpringAnnotationScanner springAnnotationScanner() { return new SpringAnnotationScanner(socketIOServer()); } }消息处理器 MessageEventHandler
@Component @Slf4j public class MessageEventHandler { @Autowired private SocketIOServer socketIoServer; public static ConcurrentMap<String, SocketIOClient> socketIOClientMap = new ConcurrentHashMap<>(); /** * 客户端连接的时候触发 * * @param client */ @OnConnect public void onConnect(SocketIOClient client) { String mac = client.getHandshakeData().getSingleUrlParam("mac"); //存储SocketIOClient，用于发送消息 socketIOClientMap.put(mac, client); //回发消息 client.sendEvent("message", "onConnect back"); log.info("客户端:" + client.getSessionId() + "已连接,mac=" + mac); } /** * 客户端关闭连接时触发 * * @param client */ @OnDisconnect public void onDisconnect(SocketIOClient client) { log.info("客户端:" + client.getSessionId() + "断开连接"); } /** * 客户端事件 * * @param client 客户端信息 * @param request 请求信息 * @param data 客户端发送数据 */ @OnEvent(value = "messageevent") public void onEvent(SocketIOClient client, AckRequest request, Message data) { log.info("发来消息：" + data); //回发消息 client.sendEvent("messageevent", "我是服务器都安发送的信息"); //广播消息 sendBroadcast(); } /** * 广播消息 */ public void sendBroadcast() { for (SocketIOClient client : socketIOClientMap.values()) { if (client.isChannelOpen()) { client.sendEvent("Broadcast", "当前时间", System.currentTimeMillis()); } } } }html 页面
<!doctype html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width,initial-scale=1, maximum-scale=1, user-scalable=no"> <title>websocket-java-socketio</title> <script src="https://cdn.bootcss.com/socket.io/2.2.0/socket.io.js"></script> </head> <body> <h1>Socket.io Test</h1> <div><p id="status">Waiting for input</p></div> <div><p id="message">hello world!</p></div> <button id="connect" onClick='connect()'/>Connect</button> <button id="disconnect" onClick='disconnect()'>Disconnect</button> <button id="send" onClick='send()'/>Send Message</button> </body> <script type="text/javascript"> /** * 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, * 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 **/ var socket = io.connect("http://localhost:9092?mac=2"); var firstconnect = true; function connect() { if(firstconnect) { //socket.on('reconnect', function(){ status_update("Reconnected to Server"); }); //socket.on('reconnecting', function( nextRetry ){ status_update("Reconnecting in " //+ nextRetry + " seconds"); }); //socket.on('reconnect_failed', function(){ message("Reconnect Failed"); }); //firstconnect = false; } else { socket.socket.reconnect(); } } //监听服务器连接事件 socket.on('connect', function(){ status_update("Connected to Server"); }); //监听服务器关闭服务事件 socket.on('disconnect', function(){ status_update("Disconnected from Server"); }); //监听服务器端发送消息事件 socket.on('messageevent', function(data) { message(data) //console.log("服务器发送的消息是："+data); }); //断开连接 function disconnect() { socket.disconnect(); } function message(data) { document.getElementById('message').innerHTML = "Server says: " + data; } function status_update(txt){ document.getElementById('status').innerHTML = txt; } function esc(msg){ return msg.replace(/</g, '<').replace(/>/g, '>'); } //点击发送消息触发 function send() { console.log("点击了发送消息，开始向服务器发送消息") var msg = "我很好的,是的．"; socket.emit('messageevent', {msgContent: msg}); }; </script> </html>运行 SpringBoot 服务器
> mvn spring-boot:run点击网页按钮
转载于:https://www.cnblogs.com/pomer-huang/p/netty-socketio.html
相关资源：JAVA上百实例源码以及开源项目