Java Servlet Filter实现Web页面执行时间过滤器

 以下是本人在项目中用Servlet Filter实现的Web页面执行时间过滤器:

package com.sunfairs.filter;import java.io.IOException;import javax.servlet.Filter;import javax.servlet.FilterChain;import javax.servlet.FilterConfig;import javax.servlet.ServletException;import javax.servlet.ServletRequest;import javax.servlet.ServletResponse;import javax.servlet.http.HttpServletRequest;import org.apache.commons.logging.Log;import org.apache.commons.logging.LogFactory;public class TimerFilter implements Filter {private static final Log log = LogFactory.getLog(TimerFilter.class);public static final String DEFAULT_TIMER_ATTRIBUTE = "sunfairs.shop.jsp.timer";private String key;public void destroy() {}public void doFilter(ServletRequest request, ServletResponse response,FilterChain chain) throws IOException, ServletException {HttpServletRequest httpRequest = (HttpServletRequest) request;Timer timer = new Timer();timer.start();request.setAttribute(key, timer);chain.doFilter(request, response);timer.stop();}public void init(FilterConfig config) throws ServletException {if(config.getInitParameter("key")!=null){this.key = config.getInitParameter("key");}else{this.key = DEFAULT_TIMER_ATTRIBUTE;}}public static class Timer{private long time;public Timer(){this.time = 0l;}public long getTime() {return time;}public void start(){this.time = System.currentTimeMillis();}public void stop(){this.time = System.currentTimeMillis() - this.time;}}}