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JavaEE在线人数管理系统

2019年07月22日 | 移动技术网IT编程 | 我要评论

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

<?xml version="1.0" encoding="utf-8"?>
<web-app version="3.0" 
 xmlns="http://java.sun.com/xml/ns/javaee" 
 xmlns:xsi="http://www.w3.org/2001/xmlschema-instance" 
 xsi:schemalocation="http://java.sun.com/xml/ns/javaee 
 http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
 <display-name></display-name> 
 <filter>
 <filter-name>character</filter-name>
 <filter-class>cn.hncu.filter.characterfilter</filter-class>
 <init-param>
  <param-name>charset</param-name>
  <param-value>utf-8</param-value>
 </init-param>
 </filter>
 <filter>
 <filter-name>login</filter-name>
 <filter-class>cn.hncu.filter.loginfilter</filter-class>
 </filter>

 <filter-mapping>
 <filter-name>character</filter-name>
 <url-pattern>/*</url-pattern>
 </filter-mapping>
 <filter-mapping>
 <filter-name>login</filter-name>
 <url-pattern>/servlet/*</url-pattern>
 <url-pattern>/jsps/*</url-pattern>
 <dispatcher>request</dispatcher>
 <dispatcher>forward</dispatcher>
 </filter-mapping>


 <listener>
 <listener-class>cn.hncu.listener.mysessionlistener</listener-class>
 </listener>

 <servlet>
 <servlet-name>loginservlet</servlet-name>
 <servlet-class>cn.hncu.servlet.loginservlet</servlet-class>
 </servlet>
 <servlet>
 <servlet-name>showservlet</servlet-name>
 <servlet-class>cn.hncu.servlet.showservlet</servlet-class>
 </servlet>
 <servlet>
 <description>this is the description of my j2ee component</description>
 <display-name>this is the display name of my j2ee component</display-name>
 <servlet-name>kickoutservlet</servlet-name>
 <servlet-class>cn.hncu.servlet.kickoutservlet</servlet-class>
 </servlet>
 <servlet>
 <description>this is the description of my j2ee component</description>
 <display-name>this is the display name of my j2ee component</display-name>
 <servlet-name>loginoutservlet</servlet-name>
 <servlet-class>cn.hncu.servlet.loginoutservlet</servlet-class>
 </servlet>



 <servlet-mapping>
 <servlet-name>loginservlet</servlet-name>
 <url-pattern>/loginservlet</url-pattern>
 </servlet-mapping>
 <servlet-mapping>
 <servlet-name>showservlet</servlet-name>
 <url-pattern>/servlet/showservlet</url-pattern>
 </servlet-mapping>
 <servlet-mapping>
 <servlet-name>kickoutservlet</servlet-name>
 <url-pattern>/servlet/kickoutservlet</url-pattern>
 </servlet-mapping>
 <servlet-mapping>
 <servlet-name>loginoutservlet</servlet-name>
 <url-pattern>/servlet/loginoutservlet</url-pattern>
 </servlet-mapping>


 <welcome-file-list>
 <welcome-file>index.jsp</welcome-file>
 </welcome-file-list>
</web-app>

index.jsp

<%@ page language="java" import="java.util.*" pageencoding="utf-8"%>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<!doctype html public "-//w3c//dtd html 4.01 transitional//en">
<html>
 <head>
 <title>在线人信息管理</title>
 </head>

 <body>
 <h2>在线人信息管理</h2>
 <h3>会员登录</h3>
 <c:if test="${ empty sessionscope.user.name}" var="boo">
  <form action='<c:url value="/loginservlet"></c:url>'>
   姓名:<input type="text" name="name"><br/>
    <input type="submit" value="登录"><br/>
  </form>
 </c:if>
 <c:if test="${!boo}" >
  欢迎回来,${ sessionscope.user.name}
  <c:if test="${ sessionscope.user.admin}" var="bo">
   管理员
  </c:if>
  <c:if test="${!bo}" >
   会员
  </c:if>
 </c:if>
 <br/>
  <c:if test="${!boo}" var="boo">
  <a href='<c:url value="/servlet/showservlet"/>'>查看在线人信息</a><br/>
  <a href='<c:url value="/servlet/loginoutservlet"/>'>安全退出</a><br/>
  </c:if>

 </body>
</html>

/jsps/show.jsp

<%@ page language="java" import="java.util.*" pageencoding="utf-8"%>
<%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<!doctype html public "-//w3c//dtd html 4.01 transitional//en">
<html>
<head>
<title>在线人信息</title>
<style type="text/css">
 table {
  color: green;
  border: 1px solid blue;
  border-collapse: collapse;
  width: 500px;
  margin: auto;
 }
 td {
  border: 1px solid blue;
 }
 th {
  border: 1px solid blue;
 }
 body {
  text-align: center;
 }
</style>
 <meta http-equiv="refresh" content="3">
</head>

<body>
 <table>
  <tr>
   <th>姓名</th>
   <th>上线时间</th>
   <th>最后访问时间</th>
   <th>ip</th>
   <th>操作</th>
  </tr>

  <c:foreach items="${requestscope.onlines}" var="online">
  <tr>
   <td>
    <c:if test="${!empty online.user }" var="boo">
      ${online.user.name }
    </c:if>
    <c:if test="${empty online.user }">
      游客
    </c:if>
   </td>
   <td>${online.createtime }</td>
   <td>${online.lastaccessedtime }</td>
   <td>${online.ip }</td>
   <td>
    <c:if test="${online.user!=sessionscope.user }"> 
     <c:if test="${!online.user.admin&&boo}">
       <a href='<c:url value="/servlet/kickoutservlet?id=${online.id }"/>' >踢出</a>
     </c:if>
    </c:if>
   </td>
  </tr>
  </c:foreach>
 </table>
</body>
</html>

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<string, httpsession> onlines= (map<string, httpsession>) se.getsession().getservletcontext().getattribute("onlines");
  if(onlines==null){
   onlines=collections.synchronizedmap(new hashmap<string, httpsession>());//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<string, httpsession> onlines= (map<string, httpsession>) 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<string, httpsession> onlines=(map<string, httpsession>) request.getservletcontext().getattribute("onlines");
  list<map<string, object>> list=new arraylist<map<string,object>>();//吧online封装成list
  if (onlines!=null) {
   iterator<httpsession> it = onlines.values().iterator();
   while (it.hasnext()) {
    httpsession s = it.next();
    map<string, object> map = new hashmap<string, object>();
    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<string, httpsession> onlines=(map<string, httpsession>) 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");

 }

}

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JavaEE在线人数管理系统

2019年07月22日 | 移动技术网IT编程 | 我要评论

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