ASP程序員經常要在global.asa文(wén)件(jiàn)内處理(lǐ)Application_start,Session_Start等

事件(jiàn)，如(rú)：用(yòng)戶驗證、重定向不同編碼頁面等，十分(fēn)方便，然而一向頗受歡迎的(de)JSP并不很支持這種處理(lǐ)，除了商業(yè)化服務器(qì)JRun支持global.jsa以外，竟連應用(yòng)率極高(gāo)的(de)開(kāi)放(fàng)源碼服務器(qì)Tomcat都(dōu)不支持，這給JSP的(de)開(kāi)發造成不小(xiǎo)障礙,雖然早期Tomcat(5.0以前版本)下可(kě)以通過以下方式實現Session-start事件(jiàn)處理(lǐ)

1.       添加Session

session.put(“bind.listener”,new MyListener(getServletContext())

2.       定義MyListener類

import javax.servlet.http.*;

import javax.servlet.*;

public class MyListener implements HttpSessionBindingListener

{

        ServletContext context;

        public ODSessionListener(ServletContext context)

        {

               this.context=context;

        }

        public void valueBound(HttpSessionBindingEvent event)

        {

               System.out.println(“bound”);

        }

        public void valueUnBound(HttpSessionBindingEvent event)

        {

               System.out.println(“unbound”);

        }

}

但(dàn)處理(lǐ)前提是Session已經建立，并且不能(néng)在Session創建時處理(lǐ)驗證等事件(jiàn)，通過研究Servlet 2.4（Tomcat5.0内建）終于找到(dào)一種可(kě)行(xíng)方法，實現方法如(rú)下：

//---------------------- SessionListener.java----------------------------------------------------

package listeners;

import javax.servlet.ServletContext;

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;

// ServletRequestListener爲Servlet2.4新增接口
import javax.servlet.ServletRequestListener;

import javax.servlet.ServletRequestEvent;

import javax.servlet.http.HttpServletRequest;

public final class SessionListener

implements HttpSessionListener,ServletRequestListener {

private  HttpServletRequest  request;

public void requestDestroyed(ServletRequestEvent sre) { }

public  void requestInitialized(ServletRequestEvent sre)

 {

          request=(HttpServletRequest)sre.getServletRequest();

    }

    public void sessionCreated(HttpSessionEvent event) {

        String logMsg=event.getSession().getId()

            +"'  '"+request.getRemoteAddr()

            +":"+request.getRemotePort();

        log("sessionCreated('" + logMsg + "')");

    }

    public void sessionDestroyed(HttpSessionEvent event)