servlet监听器

监听器
ServletContextListener  监听servlet的初始化和结束
httpSessionListener      监听session的创建和结束 ,可以利用这个来统计在线登录的人数..
package com.zh;

import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;

public class LoginListener implements HttpSessionListener{
private static int count;
public static int getCount(){
return count;
}
public void sessionCreated(HttpSessionEvent arg0) {
// TODO Auto-generated method stub
count++;
}

public void sessionDestroyed(HttpSessionEvent arg0) {
// TODO Auto-generated method stub
count--;
}
}

注意要在web.xml文件中 设置
<listener>
<listener-class>com.zh.Test1</listener-class>
</listener>

ServletContextAttributeListener    当servletContext对象被设置,删除,替换
HttpSessionAttributeListener      当HttpSession对象被设置,删除,替换
ServletRequestAttributeListener    当ServletRequest对象被设置,删除,替换
HttpSessionBindingListener        当HttpSession中添加属性和删除属性
注意: HttpSessionBindingListener不用在web.xml中设置

监听器

ServletContextListener 监听servlet的初始化和结束

httpSessionListener 监听session的创建和结束 ,可以利用这个来统计在线登录的人数..

package com.zh;

import javax.servlet.http.HttpSessionEvent;

import javax.servlet.http.HttpSessionListener;

public class LoginListener implements HttpSessionListener{

private static int count;

public static int getCount(){

return count;

}

public void sessionCreated(HttpSessionEvent arg0) {

// TODO Auto-generated method stub

count++;

}

public void sessionDestroyed(HttpSessionEvent arg0) {

// TODO Auto-generated method stub

count--;

}

}

注意要在web.xml文件中 设置

<listener>

<listener-class>com.zh.Test1</listener-class>

</listener>

ServletContextAttributeListener 当servletContext对象被设置,删除,替换

HttpSessionAttributeListener 当HttpSession对象被设置,删除,替换

ServletRequestAttributeListener 当ServletRequest对象被设置,删除,替换

HttpSessionBindingListener 当HttpSession中添加属性和删除属性

注意: HttpSessionBindingListener不用在web.xml中设置