Java实现websocket 的两种方法
1.Tomcat实现websocket方法
1.1 新建JavaWeb测试项目

1.2 在pom.xml中添加Jar包依
<dependency> <groupId>javax</groupId> <artifactId>javaee-api</artifactId> <version>7.0</version> <scope>provided</scope> </dependency>
2. Spring整合websocket方法(基于Spring MVC 框架)
2.1 WebSocketConfig.java
这个类是配置类,所以需要在spring mvc配置文件中加入对这个类的扫描,第一个addHandler是对正常连接的配置,第二个是如果浏览器不支持websocket,使用socketjs模拟websocket的连接.
package com.websocket; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.web.socket.config.annotation.EnableWebSocket; import org.springframework.web.socket.config.annotation.WebSocketConfigurer; import org.springframework.web.socket.config.annotation.WebSocketHandlerRegistry; import org.springframework.web.socket.handler.TextWebSocketHandler; @Configuration @EnableWebSocket public class WebSocketConfig implements WebSocketConfigurer { @Override public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) { registry.addHandler(chatMessageHandler(),"/webSocketServer").addInterceptors(new ChatHandshakeInterceptor()); registry.addHandler(chatMessageHandler(), "/sockjs/webSocketServer").addInterceptors(new ChatHandshakeInterceptor()).withSockJS(); } @Bean public TextWebSocketHandler chatMessageHandler(){ return new ChatMessageHandler(); } }
2.2 ChatHandshakeInterceptor.java
这个类的作用就是在连接成功前和成功后增加一些额外的功能,Constants.java类是一个工具类,两个常量
package com.websocket; import java.util.Map; import org.apache.shiro.SecurityUtils; import org.springframework.http.server.ServerHttpRequest; import org.springframework.http.server.ServerHttpResponse; import org.springframework.web.socket.WebSocketHandler; import org.springframework.web.socket.server.support.HttpSessionHandshakeInterceptor; public class ChatHandshakeInterceptor 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 String userName = * (String) session.getAttribute(Constants.SESSION_USERNAME); if * (userName==null) { userName="default-system"; } * attributes.put(Constants.WEBSOCKET_USERNAME,userName); * * } } */ //使用userName区分WebSocketHandler,以便定向发送消息(使用shiro获取session,或是使用上面的方式) String userName = (String) SecurityUtils.getSubject().getSession().getAttribute(Constants.SESSION_USERNAME); if (userName == null) { userName = "default-system"; } attributes.put(Constants.WEBSOCKET_USERNAME, userName); return super.beforeHandshake(request, response, wsHandler, attributes); } @Override public void afterHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler, Exception ex) { System.out.println("After Handshake"); super.afterHandshake(request, response, wsHandler, ex); } }
2.3 ChatMessageHandler.java
这个类是对消息的一些处理,比如是发给一个人,还是发给所有人,并且前端连接时触发的一些动作
package com.websocket; import java.io.IOException; import java.util.ArrayList; import org.apache.log4j.Logger; import org.springframework.web.socket.CloseStatus; import org.springframework.web.socket.TextMessage; import org.springframework.web.socket.WebSocketSession; import org.springframework.web.socket.handler.TextWebSocketHandler; public class ChatMessageHandler extends TextWebSocketHandler { private static final ArrayList<WebSocketSession> users;// 这个会出现性能问题,最好用Map来存储,key用userid private static Logger logger = Logger.getLogger(ChatMessageHandler.class); static { users = new ArrayList<WebSocketSession>(); } /** * 连接成功时候,会触发UI上onopen方法 */ @Override public void afterConnectionEstablished(WebSocketSession session) throws Exception { System.out.println("connect to the websocket success......"); users.add(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("你将收到的离线"); // session.sendMessage(returnMessage); } /** * 在UI在用js调用websocket.send()时候,会调用该方法 */ @Override protected void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception { sendMessageToUsers(message); //super.handleTextMessage(session, message); } /** * 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; } } } /** * 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(); } } } @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; } }
2.4 spring-mvc.xml
xmlns:websocket="http://www.springframework.org/schema/websocket" http://www.springframework.org/schema/websocket <a target="_blank" href="http://www.springframework.org/schema/websocket/spring-websocket-4.1.xsd">http://www.springframework.org/schema/websocket/spring-websocket-4.1.xsd</a>
2.5 客户端
<script type="text/javascript" src="http://localhost:8080/Bank/js/sockjs-0.3.min.js"></script> <script> var websocket; if ('WebSocket' in window) { websocket = new WebSocket("ws://" + document.location.host + "/Bank/webSocketServer"); } else if ('MozWebSocket' in window) { websocket = new MozWebSocket("ws://" + document.location.host + "/Bank/webSocketServer"); } else { websocket = new SockJS("http://" + document.location.host + "/Bank/sockjs/webSocketServer"); } websocket.onopen = function(evnt) {}; websocket.onmessage = function(evnt) { $("#test").html("(<font color='red'>" + evnt.data + "</font>)") }; websocket.onerror = function(evnt) {}; websocket.onclose = function(evnt) {} $('#btn').on('click', function() { if (websocket.readyState == websocket.OPEN) { var msg = $('#id').val(); //调用后台handleTextMessage方法 websocket.send(msg); } else { alert("连接失败!"); } }); </script>