Listener and Filter Write classification statistics IP access times

Servletcontextlistenertest class

Set Listener Listening

Package Com.zhiyou.ipadr.demo;

Import Java.util.HashMap;
Import Java.util.Map;

Import Javax.servlet.ServletContext;
Import javax.servlet.ServletContextEvent;
Import Javax.servlet.ServletContextListener;
Import Javax.servlet.annotation.WebListener;

@WebListener public
class Servletcontextlistenertest implements Servletcontextlistener {

    @Override
    public void contextinitialized (Servletcontextevent sce) {
        //create Map map< in Servletcontextlistener init method
        String,integer> map=new hashmap<> ();
        Get ServletContext
        ServletContext context = Sce.getservletcontext ();
        Context.setattribute ("Mapip", map);

    @Override public
    void contextdestroyed (Servletcontextevent sce) {


    }

}

Ipcountfilter class

Package Com.zhiyou.ipadr.demo;
Import java.io.IOException;

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.annotation.WebFilter; @WebFilter (urlpatterns= "*") public class Ipcountfilter implements Filter {@Override public void init (filterconf IG Filterconfig) throws servletexception {} @Override public void Dofilter (ServletRequest request, SERVLETR Esponse response, Filterchain chain) throws IOException, servletexception {//classification statistics IP access times SERVL
        Etcontext context = Request.getservletcontext ();

        map<string,integer> map = (map<string,integer>) context.getattribute ("Mapip");
        Gets the requested IP address String IP = request.getremoteaddr (); Determine if the map has access to the IP number if (map.cOntainskey (IP)) {map.put (IP, map.get (IP) +1);
        }else{map.put (IP, 1);

        //re-put ServletContext context.setattribute ("Mapip", map);

        SYSTEM.OUT.PRINTLN (Map.get (IP));
    Release Chain.dofilter (request, response);
 @Override public void Destroy () {}}

index.jsp

http://localhost:8080/week09_day04_3/index.jsp
Refresh more than once, several times is the site traffic, because the listener annotation for @webfilter (urlpatterns= "*"), that is, listening to all the action. The number of times to refresh is the amount of Web site visits

<%@ page language= "java" contenttype= "text/html; Charset=utf-8 "
    pageencoding=" UTF-8 "%>
<%
    String path = Request.getcontextpath ();
    String basepath = request.getscheme () + "://" + request.getservername () + ":" + request.getserverport () + path + "/";
%>
<! DOCTYPE HTML PUBLIC "-//w3c//dtd HTML 4.01 transitional//en" "Http://www.w3.org/TR/html4/loose.dtd" >
 
show.jsp 
http://localhost:8080/week09_day04_3/show.jsp
Table shows IP and display times

<%@ page language= "java" contenttype= "text/html; 
    Charset=utf-8 "pageencoding=" UTF-8 "%> <%@ taglib prefix=" C "uri=" Http://java.sun.com/jsp/jstl/core "%> <%
    String path = Request.getcontextpath ();
String basepath = request.getscheme () + "://" + request.getservername () + ":" + request.getserverport () + path + "/"; %> <!
DOCTYPE HTML PUBLIC "-//w3c//dtd HTML 4.01 transitional//en" "Http://www.w3.org/TR/html4/loose.dtd" >