Amin's Note

package com.chinajavaworld.util;

 

import java.io.IOException;

import javax.servlet.*;

import javax.servlet.http.HttpServletRequest;

 

public class TimerFilter

    implements Filter

{

    public static class Timer

    {

 

        long time;

 

        public void start()

        {

            time = System.currentTimeMillis();

        }

 

        public void stop()

        {

            time = System.currentTimeMillis() - time;

        }

 

        public long getTime()

        {

            return time;

        }

 

        public Timer()

        {

            time = 0L;

        }

    }

 

 

    public static final String DEFAULT_TIMER_ATTRIBUTE = "cjw.timer";

    private String key;

 

    public TimerFilter()

    {

        key = null;

    }

 

    public void init(FilterConfig filterConfig)

        throws ServletException

    {

        if(filterConfig.getInitParameter("key") != null)

            key = filterConfig.getInitParameter("key");

        else

            key = DEFAULT_TIMER_ATTRIBUTE;

    }

 

    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain)

        throws IOException, ServletException

    {

        HttpServletRequest request = (HttpServletRequest)servletRequest;

        Timer timer = new Timer();

        timer.start();

        request.setAttribute(key, timer);

        filterChain.doFilter(servletRequest, servletResponse);

        timer.stop();

        handleTimer(timer);

    }

 

    public void handleTimer(Timer timer1)

    {

    }

 

    public void destroy()

    {

    }

}

<filter>

        <filter-name>Timer</filter-name>

        <filter-class>com.chinajavaworld.util.TimerFilter</filter-class>

    </filter>

    <filter-mapping>

        <filter-name>Timer</filter-name>

        <url-pattern>/*</url-pattern>

    </filter-mapping>

<%

    // Get the timer from the request as an attribute if it exists:

    TimerFilter.Timer timer

            = (TimerFilter.Timer)request.getAttribute(TimerFilter.DEFAULT_TIMER_ATTRIBUTE);

    if (timer != null) {

        timer.stop();

%>

    <p style="font-size:11px;">Processed in <b><%= timer.getTime() %></b> ms

<%}%>