JavaEE在线人数管理系统

这篇博客是filter、listener和servlet技术的相关总结，实现了简单的显示在线人数、在线人详细信息、管理员踢人功能

下面是详细代码

web.xml

  
 
 character
 cn.hncu.filter.CharacterFilter
 
  charset
  utf-8
 
 
 
 login
 cn.hncu.filter.LoginFilter
 

 
 character
 /*
 
 
 login
 /servlet/*
 /jsps/*
 REQUEST
 FORWARD
 


 
 cn.hncu.listener.MySessionListener
 

 
 LoginServlet
 cn.hncu.servlet.LoginServlet
 
 
 ShowServlet
 cn.hncu.servlet.ShowServlet
 
 
 This is the description of my J2EE component
 This is the display name of my J2EE component
 KickOutServlet
 cn.hncu.servlet.KickOutServlet
 
 
 This is the description of my J2EE component
 This is the display name of my J2EE component
 LoginOutServlet
 cn.hncu.servlet.LoginOutServlet
 



 
 LoginServlet
 /LoginServlet
 
 
 ShowServlet
 /servlet/ShowServlet
 
 
 KickOutServlet
 /servlet/KickOutServlet
 
 
 LoginOutServlet
 /servlet/LoginOutServlet
 


 
 index.jsp
 

index.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>


 
 
 

 
 
在线人信息管理
 
会员登录
 
  

   姓名:

    

  
 
 
  欢迎回来,${ sessionScope.user.name}
  
   管理员
  
  
   会员
  
 
 

  
  查看在线人信息

  安全退出

  

 

/jsps/show.jsp

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>





 



 
  

  

   
姓名
   
上线时间
   
最后访问时间
   
ip
   
操作
  

  

   

    
      ${online.user.name }
    
    
      游客
    
   
   
${online.createTime }
   
${online.lastAccessedTime }
   
${online.ip }
   

     
     
       踢出
     
    
   
  
  
 

User.java(值对象）

package cn.hncu.domain;

public class User {
 private String name;
 private boolean admin;
 public String getName() {
  return name;
 }
 public void setName(String name) {
  this.name = name;
 }
 public boolean isAdmin() {
  return admin;
 }
 public void setAdmin(boolean admin) {
  this.admin = admin;
 }
 @Override
 public String toString() {
  return "User [name=" + name + ", admin=" + admin + "]";
 }
}

MySessionListener.java(监听器）

package cn.hncu.listener;

import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

import javax.servlet.http.HttpSession;
import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;

public class MySessionListener implements HttpSessionListener{

 @Override
 public void sessionCreated(HttpSessionEvent se) {
  Map onlines= (Map) se.getSession().getServletContext().getAttribute("onlines");
  if(onlines==null){
   onlines=Collections.synchronizedMap(new HashMap());//对map进行加上同步锁
   se.getSession().getServletContext().setAttribute("onlines",onlines);
  }
  onlines.put(se.getSession().getId(), se.getSession());
 }

 @Override
 public void sessionDestroyed(HttpSessionEvent se) {
  Map onlines= (Map) se.getSession().getServletContext().getAttribute("onlines");
  if(onlines.containsKey(se.getSession().getId())){
   onlines.remove(se.getSession().getId());
  }
 }

}

CharacterFilter.java(字符过滤器）

package cn.hncu.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;

public class CharacterFilter implements Filter {
 private String charset;
 @Override
 public void init(FilterConfig filterConfig) throws ServletException {
  charset=filterConfig.getInitParameter("charset");
 }

 @Override
 public void doFilter(ServletRequest request, ServletResponse response,
   FilterChain chain) throws IOException, ServletException {
  request.setCharacterEncoding(charset);
  response.setCharacterEncoding(charset);
  HttpServletRequest req=(HttpServletRequest) request;
  if(req.getSession().getAttribute("ip")==null){
   req.getSession().setAttribute("ip", req.getRemoteAddr());
  }
  chain.doFilter(request, response);
 }

 @Override
 public void destroy() {
 }

}

LoginFilter.java(防止游客乱访问过滤器）

package cn.hncu.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 javax.servlet.http.HttpServletResponse;

public class LoginFilter implements Filter {

 @Override
 public void init(FilterConfig filterConfig) throws ServletException {

 }

 @Override
 public void doFilter(ServletRequest request, ServletResponse response,
   FilterChain chain) throws IOException, ServletException {
  HttpServletRequest req=(HttpServletRequest) request;
  if(req.getSession().getAttribute("user")==null){
   ((HttpServletResponse)response).sendRedirect(req.getContextPath()+"/index.jsp");
   return;
  }
  chain.doFilter(request, response);
 }

 @Override
 public void destroy() {
 }

}

LoginServlet.java

package cn.hncu.servlet;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import cn.hncu.domain.User;

public class LoginServlet extends HttpServlet {


 public void doGet(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {
  doPost(request, response);
 }
 public void doPost(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {
  String name=request.getParameter("name");
  User user=(User) request.getSession().getAttribute("user");
  if (user==null&&name!=null&&name.trim().length()>0) {//封装User
   user = new User();
   user.setName(name);
   if(name.equals("admin")){
    user.setAdmin(true);
   }
  }
  request.getSession().setAttribute("user", user);
  response.sendRedirect(request.getContextPath()+"/index.jsp");
 }

}

ShowServlet.java

package cn.hncu.servlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class ShowServlet extends HttpServlet {


 public void doGet(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {
  doPost(request, response);
 }


 public void doPost(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {
  Map onlines=(Map) request.getServletContext().getAttribute("onlines");
  List> list=new ArrayList>();//吧Online封装成list
  if (onlines!=null) {
   Iterator it = onlines.values().iterator();
   while (it.hasNext()) {
    HttpSession s = it.next();
    Map map = new HashMap();
    map.put("id", s.getId());
    SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    map.put("createTime", sdf.format(new Date(s.getCreationTime())));
    map.put("lastAccessedTime",sdf.format(new Date(s.getLastAccessedTime())) );
    map.put("ip", s.getAttribute("ip"));//ip信息在characterFilter中补
    map.put("user", s.getAttribute("user"));
    list.add(map);
   }
  }
  request.setAttribute("onlines", list);
  request.getRequestDispatcher("/jsps/show.jsp").forward(request, response);
 }

}

KickOutServlet.java

package cn.hncu.servlet;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Map;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class KickOutServlet extends HttpServlet {


 public void doGet(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {

  doPost(request, response);
 }
 public void doPost(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {
  String id=request.getParameter("id");
  Map onlines=(Map) request.getServletContext().getAttribute("onlines");
  if (onlines!=null) {
   if (onlines.containsKey(id)) {
    onlines.get(id).invalidate();
   }
  }
  request.getRequestDispatcher("/servlet/ShowServlet").forward(request, response);
 }

}

LoginOutServlet.java

package cn.hncu.servlet;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class LoginOutServlet extends HttpServlet {


 public void doGet(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {

  doPost(request, response);
 }

  public void doPost(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {
   request.getSession().invalidate();
   response.sendRedirect(request.getContextPath()+"/index.jsp");

 }

}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。