java web会话监听并使用spring注入

Java  /  管理员 发布于 5年前   391

 

      在java web应用中，当你想在建立会话或移除会话时，让系统做某些事情，比如说，统计在线用户，每当有用户登录时，或退出时，那么可以用下面这个监听器来监听。

      

import java.util.ArrayList;import java.util.List;import javax.servlet.ServletContextEvent;import javax.servlet.ServletContextListener;import javax.servlet.http.HttpSessionAttributeListener;import javax.servlet.http.HttpSessionBindingEvent;import javax.servlet.http.HttpSessionEvent;import javax.servlet.http.HttpSessionListener;import org.springframework.web.context.WebApplicationContext;import org.springframework.web.context.support.WebApplicationContextUtils;public class OnlineCountListener implements HttpSessionAttributeListener ,HttpSessionListener,ServletContextListener{/** * 定义监听的session属性名. */public final static String LISTENER_NAME = "user_name";/** * 定义存储客户登录session的集合. */private static List sessions = new ArrayList();private static int userSum=0;/** * session加入某值时此方法会被调用. *  * @param HttpSessionBindingEvent *            session事件 */public void attributeAdded(HttpSessionBindingEvent sbe) {if (LISTENER_NAME.equals(sbe.getName())) {sessions.add(sbe.getValue());}}/** * session失效时的监听方法. *  * @param HttpSessionBindingEvent *            session事件 */public void attributeRemoved(HttpSessionBindingEvent sbe) {if (LISTENER_NAME.equals(sbe.getName())) {sessions.remove(sbe.getValue());}}/** * session覆盖时的监听方法. *  * @param HttpSessionBindingEvent *            session事件 */public void attributeReplaced(HttpSessionBindingEvent sbe) {if (LISTENER_NAME.equals(sbe.getName())) {sessions.remove(sbe.getValue());sessions.add(sbe.getValue());}}public void sessionCreated(HttpSessionEvent arg) {userSum++;}public void sessionDestroyed(HttpSessionEvent arg) {userSum--;}/** * 返回客户登录session的集合. *  * @return */public static List getSessions() {return sessions;}public static int getMemberSum() {return sessions.size();}public static int getSum() {return userSum;}public static Boolean isExistInSessions(String username) {String user_name;for (Integer i = 0; i < sessions.size(); i++) {user_name = (String) sessions.get(i);if (user_name.equals(username)) {return true;} else {continue;}}return false;}//此方法在初始化监听器的时候会调用，用于spring注入public void contextInitialized(ServletContextEvent sce) {          WebApplicationContext applicationContext =    WebApplicationContextUtils.getWebApplicationContext(sce.getServletContext());          this.xxxService=(XxxService)applicationContext.getBean("xxxService");           }      public void contextDestroyed(ServletContextEvent sce) {                }      private XxxService xxxService;//这里是你希望注入的服务类    public XxxService  getXxxService(){      return this.xxxService;    }   public void setxxxService(XxxService xxxService){   this.xxxService=xxxService;   }}

 在web.xml中加入以下配置代码，注意必须在spring容器配置之后。

 

 

 

  <listener>       <listener-class>  com.xxx.xxx.xxx.OnlineCountListener      </listener-class>  </listener>

 然后在spring配置

 <bean id="xxxService">xxx.xxx.xxx.xxxService</bean>

 

 

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