Spring框架 websocket搭建

什么是websocket 我在这里就不在赘述,网上有很多,可以自行百度,
干脆点直接上代码 部分代码我也是网上找来的

jar 包

<dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-websocket</artifactId>
            <version>${spring.version}</version>
        </dependency>
        // 注意 websocket 版本应该和你的spring 版本保持一致 否则可能会出现意料之外的错误

配置

以下有三个类 缺一不可 关键地方也都有解释

@Configuration
@EnableWebMvc
@EnableWebSocket
public class SpringWebSocketConfig extends WebMvcConfigurerAdapter implements WebSocketConfigurer {

    @Bean
    public TextWebSocketHandler webSocketHandler() {
        return new SpringWebSocketHandler();
    }

	// 地址可以进行自定义 怎么样都可以
	// 注意 setAllowedOrigins("*") 这个是允许跨域请求 如果项目启动 前端报了 拒绝连接多半是这个原因
        @Override
    public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
        registry.addHandler(webSocketHandler(),"/websocket/socketServer")
                .addInterceptors(new SpringWebSocketHandlerInterceptor()).setAllowedOrigins("*");

        registry.addHandler(webSocketHandler(), "/sockjs/socketServer")
                .addInterceptors(new SpringWebSocketHandlerInterceptor()).withSockJS();
    }
}

public class SpringWebSocketHandler extends TextWebSocketHandler {

    //Map来存储WebSocketSession，key用USER_ID 即在线用户列表
    private static final Map<String, WebSocketSession> users;

    //用户标识
    //对应监听器从的key
    private static final String USER_ID = "WEBSOCKET_USERID";


    static {
        users =  new HashMap<String, WebSocketSession>();
    }

    public SpringWebSocketHandler() {}

    /**
     * 连接成功时候，会触发页面上onopen方法
     */
    @Override
    public void afterConnectionEstablished(WebSocketSession session) throws Exception {

        System.out.println("成功建立websocket连接!");
        Users user = (Users) session.getAttributes().get("user");
        users.put(user.getUserid(),session);

        //这块会实现自己业务，比如，当用户登录后，会把离线消息推送给用户
        //TextMessage returnMessage = new TextMessage("成功建立socket连接，你将收到的离线");
        //session.sendMessage(returnMessage);
    }

    /**
     * 关闭连接时触发
     */
    @Override
    public void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus) throws Exception {
        Users user = (Users) session.getAttributes().get("user");
        System.out.println("用户"+user.getUserid()+"已退出！");
        users.remove(user.getUserid());
        System.out.println("剩余在线用户"+users.size());
    }

    /**
     * js调用websocket.send时候，会调用该方法
     */
    @Override
    protected void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception {

        super.handleTextMessage(session, message);

        /**
         * 收到消息，自定义处理机制，实现业务
         */
        System.out.println("服务器收到消息："+message);
        //单发某人
        if(message.getPayload().startsWith("#anyone#")){
            Users user = (Users) session.getAttributes().get("user");
            sendMessageToUser(user.getUserid(), new TextMessage("服务器单发：" +message.getPayload()));

        }else if(message.getPayload().startsWith("#everyone#")){
            sendMessageToUsers(new TextMessage("服务器群发：" +message.getPayload()));
        }
    }

    @Override
    public void handleTransportError(WebSocketSession session, Throwable exception) throws Exception {
        if(session.isOpen()){
            session.close();
        }
        Users user = (Users) session.getAttributes().get("user");
        users.remove(user.getUserid());
    }

    @Override
    public boolean supportsPartialMessages() {

        return false;
    }


    /**
     * 给某个用户发送消息
     *
     * @param userId
     * @param message
     */
    public void sendMessageToUser(String userId, TextMessage message) {
        for (String id : users.keySet()) {
            if (id.equals(userId)) {
                try {
                    if (users.get(id).isOpen()) {
                        users.get(id).sendMessage(message);
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
                break;
            }
        }
    }

    /**
     * 给所有在线用户发送消息
     *
     * @param message
     */
    public void sendMessageToUsers(TextMessage message) {
        for (String userId : users.keySet()) {
            try {
                if (users.get(userId).isOpen()) {
                    users.get(userId).sendMessage(message);
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

public class SpringWebSocketHandlerInterceptor extends HttpSessionHandshakeInterceptor {

    @Override
    public boolean beforeHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler,
                                   Map<String, Object> attributes) throws Exception {
        System.out.println("Before Handshake");
        if (request instanceof ServletServerHttpRequest) {
            ServletServerHttpRequest servletRequest = (ServletServerHttpRequest) request;
            HttpSession session = servletRequest.getServletRequest().getSession(false);
            if (session != null) {
                //使用userName区分WebSocketHandler，以便定向发送消息
                //一般直接保存user实体
                Users users = (Users) session.getAttribute("user");
                if (users!=null) {
                    attributes.put("WEBSOCKET_USERID",users.getUserid());
                }
            }
        }
        return super.beforeHandshake(request, response, wsHandler, attributes);

    }

    @Override
    public void afterHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler,
                               Exception ex) {
        super.afterHandshake(request, response, wsHandler, ex);
    }
}

前端

// 引入这个外部js
<script type="text/javascript" src="http://cdn.bootcss.com/sockjs-client/1.1.1/sockjs.js">
</script>

 var websocket = null;
	// * 表示和你地址栏上的地址应该是一样的 不然会报404
    if ('WebSocket' in window) {
        websocket = new WebSocket("ws://*/websocket/socketServer");
    }
    else if ('MozWebSocket' in window) {
        websocket = new MozWebSocket("ws://*/websocket/socketServer");
    }
    else {
        websocket = new SockJS("http://*/sockjs/socketServer");
    }
    websocket.onopen = onOpen;
    websocket.onmessage = onMessage;
    websocket.onerror = onError;
    websocket.onclose = onClose;

    function onOpen(openEvt) {
    }

    function onMessage(evt) {
    // 后端发送消息会在此接收到
    }
 
    window.close=function()
    {
        websocket.onclose();
    };

后端发送数据

// 测试类
@Controller
public class WebSocketController {

	// webSocket 注入
    @Bean
    public SpringWebSocketHandler infoHandler() {
        return new SpringWebSocketHandler();
    }

	// 这里就是一个发送某个用户消息的例子!
    @RequestMapping("/websocket/send")
    @ResponseBody
    public String send(HttpServletRequest request,String text) {
        String username = request.getParameter("username");
        infoHandler().sendMessageToUser(username, new TextMessage(text));
        return null;
    }


}