Spring+Websocket实现消息的推送

来源：互联网发布：node 编辑：程序博客网时间：2024/04/30 09:01

本文主要有三个步骤 1、用户登录后建立websocket连接，默认选择websocket连接，如果浏览器不支持，则使用sockjs进行模拟连接 2、建立连接后，服务端返回该用户的未读消息 3、服务端进行相关操作后，推送给某一个用户或者所有用户新消息相关环境 Spring4.0.6(要选择4.0+),tomcat7.0.5

Websocet服务端实现

WebSocketConfig.java

@Configuration@EnableWebMvc@EnableWebSocketpublic class WebSocketConfig extends WebMvcConfigurerAdapter implements WebSocketConfigurer {    @Override    public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {        registry.addHandler(systemWebSocketHandler(),"/webSocketServer").addInterceptors(new WebSocketHandshakeInterceptor());        registry.addHandler(systemWebSocketHandler(), "/sockjs/webSocketServer").addInterceptors(new WebSocketHandshakeInterceptor())                .withSockJS();    }    @Bean    public WebSocketHandler systemWebSocketHandler(){        return new SystemWebSocketHandler();    }}

不要忘记在springmvc的配置文件中配置对此类的自动扫描

<context:component-scan base-package="com.ldl.origami.websocket" />

@Configuration

@EnableWebMvc
@EnableWebSocket
这三个大致意思是使这个类支持以@Bean的方式加载bean，并且支持springmvc和websocket，不是很准确大致这样，试了一下@EnableWebMvc不加也没什么影响，@Configuration本来就支持springmvc的自动扫描

registry.addHandler(systemWebSocketHandler(),"/webSocketServer").addInterceptors(new WebSocketHandshakeInterceptor())

用来注册websocket server实现类，第二个参数是访问websocket的地址

registry.addHandler(systemWebSocketHandler(), "/sockjs/webSocketServer").addInterceptors(new WebSocketHandshakeInterceptor())                .withSockJS();    }

这个是使用Sockjs的注册方法
首先SystemWebSocketHandler.java

public class SystemWebSocketHandler implements WebSocketHandler {    private static final Logger logger;    private static final ArrayList<WebSocketSession> users;    static {        users = new ArrayList<>();        logger = LoggerFactory.getLogger(SystemWebSocketHandler.class);    }    @Autowired    private WebSocketService webSocketService;    @Override    public void afterConnectionEstablished(WebSocketSession session) throws Exception {        logger.debug("connect to the websocket success......");        users.add(session);        String userName = (String) session.getAttributes().get(Constants.WEBSOCKET_USERNAME);        if(userName!= null){            //查询未读消息            int count = webSocketService.getUnReadNews((String) session.getAttributes().get(Constants.WEBSOCKET_USERNAME));            session.sendMessage(new TextMessage(count + ""));        }    }    @Override    public void handleMessage(WebSocketSession session, WebSocketMessage<?> message) throws Exception {        //sendMessageToUsers();    }    @Override    public void handleTransportError(WebSocketSession session, Throwable exception) throws Exception {        if(session.isOpen()){            session.close();        }        logger.debug("websocket connection closed......");        users.remove(session);    }    @Override    public void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus) throws Exception {        logger.debug("websocket connection closed......");        users.remove(session);    }    @Override    public boolean supportsPartialMessages() {        return false;    }    /**     * 给所有在线用户发送消息     *     * @param message     */    public void sendMessageToUsers(TextMessage message) {        for (WebSocketSession user : users) {            try {                if (user.isOpen()) {                    user.sendMessage(message);                }            } catch (IOException e) {                e.printStackTrace();            }        }    }    /**     * 给某个用户发送消息     *     * @param userName     * @param message     */    public void sendMessageToUser(String userName, TextMessage message) {        for (WebSocketSession user : users) {            if (user.getAttributes().get(Constants.WEBSOCKET_USERNAME).equals(userName)) {                try {                    if (user.isOpen()) {                        user.sendMessage(message);                    }                } catch (IOException e) {                    e.printStackTrace();                }                break;            }        }    }}

相关内容大家一看就能明白，就不多解释了

然后WebSocketHandshakeInterceptor.java

public class WebSocketHandshakeInterceptor implements HandshakeInterceptor {    private static Logger logger = LoggerFactory.getLogger(HandshakeInterceptor.class);    @Override    public boolean beforeHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler, Map<String, Object                > attributes) throws Exception {        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                String userName = (String) session.getAttribute(Constants.SESSION_USERNAME);                attributes.put(Constants.WEBSOCKET_USERNAME,userName);            }        }        return true;    }    @Override    public void afterHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler, Exception exception) {    }}

个的主要作用是取得当前请求中的用户名，并且保存到当前的WebSocketHandler中，以便确定WebSocketHandler所对应的用户，具体可参考HttpSessionHandshakeInterceptor

用户登录建立websocket连接

index.jsp

<script type="text/javascript" src="http://localhost:8080/Origami/websocket/sockjs-0.3.min.js"></script>        <script>            var websocket;            if ('WebSocket' in window) {                websocket = new WebSocket("ws://localhost:8080/Origami/webSocketServer");            } else if ('MozWebSocket' in window) {                websocket = new MozWebSocket("ws://localhost:8080/Origami/webSocketServer");            } else {                websocket = new SockJS("http://localhost:8080/Origami/sockjs/webSocketServer");            }            websocket.onopen = function (evnt) {            };            websocket.onmessage = function (evnt) {                $("#msgcount").html("(<font color='red'>"+evnt.data+"</font>)")            };            websocket.onerror = function (evnt) {            };            websocket.onclose = function (evnt) {            }        </script>

使用sockjs时要注意

1、这两个的写法

<script type="text/javascript" src="http://localhost:8080/Origami/websocket/sockjs-0.3.min.js"></script>

websocket = new SockJS("http://localhost:8080/Origami/sockjs/webSocketServer");

2、web.xml中

<web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee"    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_1.xsd">

version

web-app_3_1.xsd

这两个的版本都要是3.0+

然后在这个servlet中加入

<async-supported>true</async-supported>

<servlet>        <servlet-name>appServlet</servlet-name>        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>        <init-param>            <param-name>contextConfigLocation</param-name>            <param-value>classpath*:servlet-context.xml</param-value>        </init-param>        <load-on-startup>1</load-on-startup>        <async-supported>true</async-supported>    </servlet>

然后所有的filter中也加入

<async-supported>true</async-supported>

3、添加相关依赖

<dependency>            <groupId>com.fasterxml.jackson.core</groupId>            <artifactId>jackson-annotations</artifactId>            <version>2.3.0</version>        </dependency>        <dependency>            <groupId>com.fasterxml.jackson.core</groupId>            <artifactId>jackson-core</artifactId>            <version>2.3.1</version>        </dependency>        <dependency>            <groupId>com.fasterxml.jackson.core</groupId>            <artifactId>jackson-databind</artifactId>            <version>2.3.3</version>        </dependency>

好了，现在websocket可以正常建立起来了

返回用户未读的消息

当连接建立后，会进入SystemWebSocketHandler的afterConnectionEstablished方法，代码看上边，取出WebSocketHandshakeInterceptor中保存的用户名

查询信息后使用session.sendMessage(new TextMessage(count + “”));返回给用户，从哪来回哪去

服务端推送消息给用户

@Controllerpublic class AdminController {    static Logger logger = LoggerFactory.getLogger(AdminController.class);    @Autowired(required = false)    private AdminService adminService;    @Bean    public SystemWebSocketHandler systemWebSocketHandler() {        return new SystemWebSocketHandler();    }    @RequestMapping("/auditing")    @ResponseBody    public String auditing(HttpServletRequest request){        //无关代码都省略了        int unReadNewsCount = adminService.getUnReadNews(username);        systemWebSocketHandler().sendMessageToUser(username, new TextMessage(unReadNewsCount + ""));        return result;    }}

在这里可以使用sendMessageToUser给某个用户推送信息，也可以使用sendMessageToUsers给所有用户推送信息

原文地址：https://my.oschina.net/ldl123292/blog/304360

0 0