使用监听器监视会话属性

• 为该类创建一个不带参数的构造函数
• 将该类添加到WEB-INF/classes或lib目录（当在jar中时）
• 在web.xml中声明

package myServlet;

import javax.servlet.http.HttpSessionAttributeListener;
import javax.servlet.http.HttpSessionBindingEvent;

public class sessonAttributeListener implements HttpSessionAttributeListener {

	public sessonAttributeListener()
	{
		System.out.println(getClass().getName());
	}
	public void attributeAdded(HttpSessionBindingEvent arg0) {
		// TODO Auto-generated method stub

		System.out.println("attributeAdded");
	}

	public void attributeRemoved(HttpSessionBindingEvent arg0) {
		// TODO Auto-generated method stub

		System.out.println("attirbuteRemoved");
	}

	public void attributeReplaced(HttpSessionBindingEvent arg0) {
		// TODO Auto-generated method stub

		System.out.println("attributeReplaced");
	}

}

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4" 
	xmlns="http://java.sun.com/xml/ns/j2ee" 
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee 
	http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
	
 <filter>
    <filter-name>ParamFilter</filter-name>
    <filter-class>myServlet.ParamFilter</filter-class>
  </filter>
  <filter-mapping>
     <filter-name>ParamFilter</filter-name>
     <servlet-name>search</servlet-name>
  </filter-mapping>
  <filter>
    <filter-name>CookieFilter</filter-name>
    <filter-class>myServlet.CookieFilter</filter-class>
  </filter>
  
  <listener>
    <listener-class>myServlet.sessonAttributeListener</listener-class>
  </listener>
  <filter-mapping>
     <filter-name>CookieFilter</filter-name>
     <servlet-name>testCookie</servlet-name>
  </filter-mapping>
  <servlet>
    <description>This is the description of my J2EE component</description>
    <display-name>This is the display name of my J2EE component</display-name>
    <servlet-name>firstServlet</servlet-name>
    <servlet-class>firstServlet</servlet-class>
  </servlet>
  <servlet>
    <description>This is the description of my J2EE component</description>
    <display-name>This is the display name of my J2EE component</display-name>
    <servlet-name>testPath</servlet-name>
    <servlet-class>myServlet.testPath</servlet-class>
  </servlet>
  <servlet>
    <description>This is the description of my J2EE component</description>
    <display-name>This is the display name of my J2EE component</display-name>
    <servlet-name>testText</servlet-name>
    <servlet-class>myServlet.testText</servlet-class>
  </servlet>
  <servlet>
    <description>This is the description of my J2EE component</description>
    <display-name>This is the display name of my J2EE component</display-name>
    <servlet-name>search</servlet-name>
    <servlet-class>myServlet.search</servlet-class>
  </servlet>
  <servlet>
    <description>This is the description of my J2EE component</description>
    <display-name>This is the display name of my J2EE component</display-name>
    <servlet-name>testViewPoint</servlet-name>
    <servlet-class>myServlet.testViewPoint</servlet-class>
  </servlet>
  <servlet>
    <description>This is the description of my J2EE component</description>
    <display-name>This is the display name of my J2EE component</display-name>
    <servlet-name>QueryModifer</servlet-name>
    <servlet-class>myServlet.QueryModifer</servlet-class>
  </servlet>
  <servlet>
    <description>This is the description of my J2EE component</description>
    <display-name>This is the display name of my J2EE component</display-name>
    <servlet-name>UploadServlet</servlet-name>
    <servlet-class>myServlet.UploadServlet</servlet-class>
  </servlet>
  <servlet>
    <description>This is the description of my J2EE component</description>
    <display-name>This is the display name of my J2EE component</display-name>
    <servlet-name>uploadMoreFile</servlet-name>
    <servlet-class>myServlet.uploadMoreFile</servlet-class>
  </servlet>
  <servlet>
    <description>This is the description of my J2EE component</description>
    <display-name>This is the display name of my J2EE component</display-name>
    <servlet-name>ErrorGen</servlet-name>
    <servlet-class>myServlet.ErrorGen</servlet-class>
  </servlet>
  <servlet>
    <description>This is the description of my J2EE component</description>
    <display-name>This is the display name of my J2EE component</display-name>
    <servlet-name>testCookie</servlet-name>
    <servlet-class>myServlet.testCookie</servlet-class>
  </servlet>










  <servlet-mapping>
    <servlet-name>firstServlet</servlet-name>
    <url-pattern>/firstServlet</url-pattern>
  </servlet-mapping>
  <servlet-mapping>
    <servlet-name>testPath</servlet-name>
    <url-pattern>/testPath</url-pattern>
  </servlet-mapping>
  <servlet-mapping>
    <servlet-name>testText</servlet-name>
    <url-pattern>/testText</url-pattern>
  </servlet-mapping>
  <servlet-mapping>
    <servlet-name>search</servlet-name>
    <url-pattern>/search</url-pattern>
  </servlet-mapping>
  <servlet-mapping>
    <servlet-name>testViewPoint</servlet-name>
    <url-pattern>/testViewPoint</url-pattern>
  </servlet-mapping>
  <servlet-mapping>
    <servlet-name>QueryModifer</servlet-name>
    <url-pattern>/QueryModifer</url-pattern>
  </servlet-mapping>
  <servlet-mapping>
    <servlet-name>UploadServlet</servlet-name>
    <url-pattern>/UploadServlet</url-pattern>
  </servlet-mapping>
  <servlet-mapping>
    <servlet-name>uploadMoreFile</servlet-name>
    <url-pattern>/uploadMoreFile</url-pattern>
  </servlet-mapping>
  <servlet-mapping>
    <servlet-name>ErrorGen</servlet-name>
    <url-pattern>/ErrorGen</url-pattern>
  </servlet-mapping>
  <servlet-mapping>
    <servlet-name>testCookie</servlet-name>
    <url-pattern>/testCookie</url-pattern>
  </servlet-mapping>
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
  <error-page>
    <exception-type>java.lang.Throwable</exception-type>
    <location>/ErrorGen</location>
  </error-page>
  
  <context-param>
    <param-name>cookie-age</param-name>
    <param-value>31536000</param-value>
  </context-param>
  
  <session-config>
    <session-timeout>60</session-timeout>
  </session-config>
</web-app>