在SpringMVC中使用WebSocket

SpringMvc项目的搭建在这里就不做多解释，要在Spring中实现 WebSocket 必须加上 spring-websocket和

spring-messaging两个包，同样，完整的pom.xml给出如下:

< project xmlns = "http://maven.apache.org/POM/4.0.0"

     xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance"

     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0

     http://maven.apache.org/maven-v4_0_0.xsd">

     < modelVersion >4.0.0</ modelVersion >

     < groupId >com.656463</ groupId >

     < artifactId >demo-websocket</ artifactId >

     < packaging >war</ packaging >

     < name >demo-websocket Maven Webapp</ name >

     < version >0.0.1-SNAPSHOT</ version >

     < url >http://maven.apache.org</ url >

     < properties >

         < project.build.sourceEncoding >UTF-8</ project.build.sourceEncoding >

         < spring.version >4.1.6.RELEASE</ spring.version >

     </ properties >

     < dependencies >

         <!-- spring相关 -->

         < dependency >

             < groupId >org.springframework</ groupId >

             < artifactId >spring-context</ artifactId >

             < version >${spring.version}</ version >

         </ dependency >

         < dependency >

             < groupId >org.springframework</ groupId >

             < artifactId >spring-core</ artifactId >

             < version >${spring.version}</ version >

         </ dependency >

         < dependency >

             < groupId >org.springframework</ groupId >

             < artifactId >spring-beans</ artifactId >

             < version >${spring.version}</ version >

         </ dependency >

         < dependency >

             < groupId >org.springframework</ groupId >

             < artifactId >spring-aop</ artifactId >

             < version >${spring.version}</ version >

         </ dependency >

         < dependency >

             < groupId >org.springframework</ groupId >

             < artifactId >spring-context-support</ artifactId >

             < version >${spring.version}</ version >

         </ dependency >

         < dependency >

             < groupId >org.springframework</ groupId >

             < artifactId >spring-jdbc</ artifactId >

             < version >${spring.version}</ version >

         </ dependency >

         < dependency >

             < groupId >org.springframework</ groupId >

             < artifactId >spring-web</ artifactId >

             < version >${spring.version}</ version >

         </ dependency >

         < dependency >

             < groupId >org.springframework</ groupId >

             < artifactId >spring-webmvc</ artifactId >

             < version >${spring.version}</ version >

         </ dependency >

         < dependency >

             < groupId >org.springframework</ groupId >

             < artifactId >spring-websocket</ artifactId >

             < version >${spring.version}</ version >

         </ dependency >

         < dependency >

             < groupId >org.springframework</ groupId >

             < artifactId >spring-messaging</ artifactId >

             < version >${spring.version}</ version >

         </ dependency >

         < dependency >

             < groupId >org.aspectj</ groupId >

             < artifactId >aspectjweaver</ artifactId >

             < version >1.7.4</ version >

         </ dependency >

         < dependency >

             < groupId >com.google.code.gson</ groupId >

             < artifactId >gson</ artifactId >

             < version >2.7</ version >

         </ dependency >

         < dependency >

             < groupId >jstl</ groupId >

             < artifactId >jstl</ artifactId >

             < version >1.2</ version >

         </ dependency >

         < dependency >

             < groupId >taglibs</ groupId >

             < artifactId >standard</ artifactId >

             < version >1.1.2</ version >

         </ dependency >

         < dependency >

             < groupId >javax.websocket</ groupId >

             < artifactId >javax.websocket-api</ artifactId >

             < version >1.1</ version >

             < scope >provided</ scope >

         </ dependency >

         < dependency >

             < groupId >javax</ groupId >

             < artifactId >javaee-api</ artifactId >

             < version >7.0</ version >

             < scope >provided</ scope >

         </ dependency >

     </ dependencies >

     < build >

         < finalName >demo-websocket</ finalName >

         < plugins >

             < plugin >

                 < groupId >org.apache.maven.plugins</ groupId >

                 < artifactId >maven-compiler-plugin</ artifactId >

                 < version >3.0</ version >

                 < configuration >

                     < source >1.7</ source >

                     < target >1.7</ target >

                 </ configuration >

             </ plugin >

             < plugin >

                 < groupId >org.apache.tomcat.maven</ groupId >

                 < artifactId >tomcat7-maven-plugin</ artifactId >

                 < version >2.2</ version >

                 < configuration >

                     < port >8080</ port >

                     < path >/</ path >

                 </ configuration >

             </ plugin >

         </ plugins >

     </ build >

</ project >

定义一个简单的WebSocket客户端页面，这里只有一个连接和发送消息的功能，这个示例和上个示例的功能类似

<%@ page language= "java" contentType= "text/html; charset=UTF-8"           pageEncoding= "UTF-8" %> <!DOCTYPE html> <html lang= "en" > <head>      <meta charset= "utf-8" >      <title></title>      <script type= "text/javascript" src= "/static/js/jquery-1.9.1.js" ></script>      <script type= "text/javascript" >          $(function () {              var websocket;              var target = "ws://192.168.56.101:8080/hello.htm" ;              if ( 'WebSocket' in window) {                  websocket = new WebSocket(target);              } else if ( 'MozWebSocket' in window) {                  websocket = new MozWebSocket(target);              } else {                  alert( 'WebSocket is not supported by this browser.' );                  return ;              }              websocket.onopen = function (evnt) {                  $( "#tou" ).html( "链接服务器成功!" )              };              websocket.onmessage = function (evnt) {                  $( "#msg" ).html($( "#msg" ).html() + "<br/>" + evnt.data);              };              websocket.onerror = function (evnt) {              };              websocket.onclose = function (evnt) {                  $( "#tou" ).html( "与服务器断开了链接!" )              }              $( '#send' ).bind( 'click' , function () {                  send();              });              function send() {                  if (websocket != null ) {                      var message = document.getElementById( 'message' ).value;                      websocket.send(message);                  } else {                      alert( '未与服务器链接.' );                  }              }          });      </script> </head> <body> <div id= "tou" > webSocket及时聊天Demo程序</div> <div id= "msg" ></div> <input type= "text" id= "message" > <button type= "button" id= "send" > 发送</button> </body> </html>

创建握手拦截器的类 HandInterceptor ，此类实现 HandshakeInterceptor接口。此类的功能有点类似于使用原始J2EE实现的@OnOpen注解

package com._656463.demo.websocket.spring; import org.springframework.http.server.ServerHttpRequest; import org.springframework.http.server.ServerHttpResponse; import org.springframework.http.server.ServletServerHttpRequest; import org.springframework.web.socket.WebSocketHandler; import org.springframework.web.socket.server.HandshakeInterceptor; import javax.servlet.http.HttpServletRequest; import java.util.Map; /**   * 拦截器（握手）   */ public class HandInterceptor implements HandshakeInterceptor {      @Override      public boolean beforeHandshake(ServerHttpRequest request,              ServerHttpResponse response, WebSocketHandler handler,              Map<String, Object> map) throws Exception {          if (request instanceof ServletServerHttpRequest) {              HttpServletRequest req = ((ServletServerHttpRequest) request).getServletRequest();              String userName = "default-user" ;              // 使用userName区分WebSocketHandler，以便定向发送消息              // String userName = (String)              // session.getAttribute("WEBSOCKET_USERNAME");              map.put( "WEBSOCKET_USERNAME" , userName);              req.getSession().setAttribute( "WEBSOCKET_USERNAME" , userName);          }          return true ;      }      @Override      public void afterHandshake(ServerHttpRequest serverHttpRequest,              ServerHttpResponse serverHttpResponse,              WebSocketHandler webSocketHandler, Exception e) {      } }

创建一个类 WebSocketHander，实现 WebSocketHandler接口，此类的主要功能是消息处理中心，相当于使用原始J2EE API实现中的@OnMessage和@OnClose注解功能

package com._656463.demo.websocket.spring; import org.springframework.web.socket.*; import java.io.IOException; import java.util.ArrayList; import java.util.List; /**   * 消息处理中心   */ public class WebSocketHander implements WebSocketHandler {      private static final List<WebSocketSession> users = new ArrayList<WebSocketSession>();      /**       * 初次链接成功执行       *       * @param session       * @throws Exception       */      @Override      public void afterConnectionEstablished(WebSocketSession session) throws Exception {          System.out.println( "链接成功......" );          users.add(session);          String userName = (String) session.getAttributes().get( "WEBSOCKET_USERNAME" );          if (userName != null ) {              //查询未读消息              int count = 5 ;              session.sendMessage( new TextMessage(count + "" ));          }      }      /**       * 接受消息处理消息       *       * @param session       * @param message       * @throws Exception       */      @Override      public void handleMessage(WebSocketSession session, WebSocketMessage<?> message) throws Exception {          sendMessageToUsers( new TextMessage(message.getPayload() + "" ));      }      @Override      public void handleTransportError(WebSocketSession session, Throwable throwable) throws Exception {          if (session.isOpen()) {              session.close();          }          System.out.println( "链接出错，关闭链接......" );          users.remove(session);      }      @Override      public void afterConnectionClosed(WebSocketSession session, CloseStatus status) throws Exception {          System.out.println( "链接关闭......" + status.toString());          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( "WEBSOCKET_USERNAME" ).equals(userName)) {                  try {                      if (user.isOpen()) {                          user.sendMessage(message);                      }                  } catch (IOException e) {                      e.printStackTrace();                  }                  break ;              }          }      } }

有了握手拦截器和消息处理中心之后，要开启WebSocket，让他工作起来。

开启WebSocket有两种方式，一种是基于注解的方式，二是基本XML配置的方式

1、基于注解的方式

在springmvc的配置文件中，配置扫描包

<!-- websocket相关扫描，主要扫描：WebSocketConfig.java 这个类路径 -->

<context:component-scan base-package="com._656463.demo.websocket.spring"/>

创建WebSocketConfig，开启WebSocket，并注册WebSocket的请求路径

package com._656463.demo.websocket.spring; import org.springframework.context.annotation.Configuration; import org.springframework.web.servlet.config.annotation.EnableWebMvc; import org.springframework.web.socket.config.annotation.EnableWebSocket; import org.springframework.web.socket.config.annotation.WebSocketConfigurer; import org.springframework.web.socket.config.annotation.WebSocketHandlerRegistry; /**   * EnableWebSocket 开启websocket   *   * @EnableWebMvc //这个标注可以不加，如果有加，要extends WebMvcConfigurerAdapter   */ @Configuration @EnableWebSocket public class WebSocketConfig implements WebSocketConfigurer {      @Override      public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {          // 支持websocket 的访问链接          registry.addHandler( new WebSocketHander(), "/hello.htm" )                  .addInterceptors( new HandInterceptor());          // 不支持websocket的访问链接          registry.addHandler( new WebSocketHander(), "/sockjs/hello.htm" )                  .addInterceptors( new HandInterceptor())                  .withSockJS();      } }

2、基于XML配置的方式

在springmvc的配置文件中，通过websocket标签配置WebSocket

<!-- 可以在这里配置websocket的相关类,也可以用注解,详细可以查看com._656463.demo.websocket.spring.WebSocketConfig -->

<bean id= "websocket" class = "com._656463.demo.websocket.spring.WebSocketHander" />

<websocket:handlers>

     <websocket:mapping path= "/hello.htm" handler= "websocket" />

     <websocket:handshake-interceptors>

         <bean class = "com._656463.demo.websocket.spring.HandInterceptor" />

     </websocket:handshake-interceptors>

</websocket:handlers>