【转】Spring+Websocket实现消息的推送

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
@EnableWebSocket
public 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();
} }
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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" />
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@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())
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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();
}
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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;
}
}
}
}
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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) { }
}
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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>
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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>
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websocket = new SockJS("http://localhost:8080/Origami/sockjs/webSocketServer");
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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">
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version
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web-app_3_1.xsd
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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>
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<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>
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然后所有的filter中也加入

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

@Controller
public 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;
}
}
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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

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