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struts2 实现在线人数和访问源的统计。

2014-03-23 21:06 120 查看

关于listener和filter的初步学习。

1 关于在线人数的实现：

建立一个静态变量onlinecounter，当接收到一个session时，onlinecounter++，当session销毁时 onlinecounter--。

这个 listener类的代码如下：

package com.dr; 

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

import org.apache.log4j.Logger; 

public class OnlineCounter extends HttpServlet implements HttpSessionListener 
    {
    private static Logger log = Logger.getLogger(OnlineCounter.class);
    private static final long serialVersionUID = 1L;  
    private static int sessionCounter = 1;  
    public OnlineCounter(){  
        log.info("OnlineCounter initialized.");  
    }  
    public void sessionCreated(HttpSessionEvent se) {
        sessionCounter++;  
        log.info("session created:" + sessionCounter);  
    }  
    public void sessionDestroyed(HttpSessionEvent se) { 
        sessionCounter--;  
        log.info("session destroied");  
    }  
    public static int getOnlineSession() {  
        return sessionCounter;  
    } 

}

在web.xml中加入这个监听器并设置session 10分钟自动注销

<listener>   
    <listener-class>   
    com.dr.OnlineCounter   
    </listener-class>   
    </listener>  

    <session-config>
    <session-timeout>10</session-timeout><!-- 默认时间为分钟 -->
    </session-config>

2 实现访问源统计

初始化一个static 的Map，当filter接收到一次request时，获得访问地址，如果存在于map中，则值加1，否则为0。

获得访问来源的方式为String path = req.getRequestURI().toString();

这个map要通过ServletRequest request传给jsp。

filter代码：

package com.dr;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.struts2.interceptor.ApplicationAware;
public class CountTimes implements Filter {
    
    // 过滤器传来的初始化值
    private String auther ;
    private Integer time;
    static Map<String,Integer>application=new HashMap();
    
    @Override
    public void destroy() {
        
    }
    ServletContext context;
    @Override
    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {
        HttpServletRequest req = (HttpServletRequest)request ;
        HttpServletResponse resp = (HttpServletResponse)response ;
       // HttpServletApplication app=(HttpServletApplication)application;
        
        String path = req.getRequestURI().toString();
        time=application.get(path);
        if(time==null){
        	time=0;
        }
        time++;
        application.put(path, time);
        request.setAttribute("application", application);
    
            chain.doFilter(req, resp);
         }
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        //取得初始化值    
        auther = filterConfig.getInitParameter("auther");
        context  = filterConfig.getServletContext();
    }
   
}

在web.xml中注册这个filter

<filter>
         <filter-name>MyFilter</filter-name>
         <filter-class>com.dr.CountTimes</filter-class>
       <!--  初始化过滤器参数 -->
    
     </filter>
  <!--过滤器映射   -->
     <filter-mapping>
        <filter-name>MyFilter</filter-name>     
              <!--  默认拦截说有的页面 -->
         <url-pattern>/*</url-pattern> 
     </filter-mapping>

jsp文件如下：

<%@ page language="java" contentType="text/html; charset=GB18030"
    pageEncoding="GB18030" import= "com.dr.OnlineCounter"  %>
    <%@taglib prefix="s" uri="/struts-tags" %>
    <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=GB18030">
<title>Insert title here</title>
</head>
  
<body>

在线： <%=  OnlineCounter.getOnlineSession()   %>人

<br>

   <c:forEach items="${application }" var="entry" varStatus="status">  <!- 遍历map->
	<tr>
		
		<td>${ entry.key}</td>
		<td>${ entry.value}</td>
		<br>
	</tr>
	</c:forEach>

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