JavaEE在线人数管理系统

2024-03-12 18:36:02 40

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

<?xmlversion="1.0"encoding="UTF-8"?>
<web-appversion="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>ThisisthedescriptionofmyJ2EEcomponent</description>
<display-name>ThisisthedisplaynameofmyJ2EEcomponent</display-name>
<servlet-name>KickOutServlet</servlet-name>
<servlet-class>cn.hncu.servlet.KickOutServlet</servlet-class>
</servlet>
<servlet>
<description>ThisisthedescriptionofmyJ2EEcomponent</description>
<display-name>ThisisthedisplaynameofmyJ2EEcomponent</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

<%@pagelanguage="java"import="java.util.*"pageEncoding="UTF-8"%>
<%@taglibprefix="c"uri="http://java.sun.com/jsp/jstl/core"%>
<!DOCTYPEHTMLPUBLIC"-//W3C//DTDHTML4.01Transitional//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:iftest="${emptysessionScope.user.name}"var="boo">
<formaction='<c:urlvalue="/LoginServlet"></c:url>'>
姓名:<inputtype="text"name="name"><br/>
<inputtype="submit"value="登录"><br/>
</form>
</c:if>
<c:iftest="${!boo}">
欢迎回来,${sessionScope.user.name}
<c:iftest="${sessionScope.user.admin}"var="bo">
管理员
</c:if>
<c:iftest="${!bo}">
会员
</c:if>
</c:if>
<br/>
<c:iftest="${!boo}"var="boo">
<ahref='<c:urlvalue="/servlet/ShowServlet"/>'>查看在线人信息</a><br/>
<ahref='<c:urlvalue="/servlet/LoginOutServlet"/>'>安全退出</a><br/>
</c:if>

</body>
</html>

/jsps/show.jsp

<%@pagelanguage="java"import="java.util.*"pageEncoding="UTF-8"%>
<%@tagliburi="http://java.sun.com/jsp/jstl/core"prefix="c"%>
<!DOCTYPEHTMLPUBLIC"-//W3C//DTDHTML4.01Transitional//EN">
<html>
<head>
<title>在线人信息</title>
<styletype="text/css">
table{
color:green;
border:1pxsolidblue;
border-collapse:collapse;
width:500px;
margin:auto;
}
td{
border:1pxsolidblue;
}
th{
border:1pxsolidblue;
}
body{
text-align:center;
}
</style>
<metahttp-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:forEachitems="${requestScope.onlines}"var="online">
<tr>
<td>
<c:iftest="${!emptyonline.user}"var="boo">
${online.user.name}
</c:if>
<c:iftest="${emptyonline.user}">
游客
</c:if>
</td>
<td>${online.createTime}</td>
<td>${online.lastAccessedTime}</td>
<td>${online.ip}</td>
<td>
<c:iftest="${online.user!=sessionScope.user}">
<c:iftest="${!online.user.admin&&boo}">
<ahref='<c:urlvalue="/servlet/KickOutServlet?id=${online.id}"/>'>踢出</a>
</c:if>
</c:if>
</td>
</tr>
</c:forEach>
</table>
</body>
</html>

User.java(值对象）

packagecn.hncu.domain;

publicclassUser{
privateStringname;
privatebooleanadmin;
publicStringgetName(){
returnname;
}
publicvoidsetName(Stringname){
this.name=name;
}
publicbooleanisAdmin(){
returnadmin;
}
publicvoidsetAdmin(booleanadmin){
this.admin=admin;
}
@Override
publicStringtoString(){
return"User[name="+name+",admin="+admin+"]";
}
}

MySessionListener.java(监听器）

packagecn.hncu.listener;

importjava.util.Collections;
importjava.util.HashMap;
importjava.util.Map;

importjavax.servlet.http.HttpSession;
importjavax.servlet.http.HttpSessionEvent;
importjavax.servlet.http.HttpSessionListener;

publicclassMySessionListenerimplementsHttpSessionListener{

@Override
publicvoidsessionCreated(HttpSessionEventse){
Map<String,HttpSession>onlines=(Map<String,HttpSession>)se.getSession().getServletContext().getAttribute("onlines");
if(onlines==null){
onlines=Collections.synchronizedMap(newHashMap<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
publicvoidsessionDestroyed(HttpSessionEventse){
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）

packagecn.hncu.filter;

importjava.io.IOException;

importjavax.servlet.Filter;
importjavax.servlet.FilterChain;
importjavax.servlet.FilterConfig;
importjavax.servlet.ServletException;
importjavax.servlet.ServletRequest;
importjavax.servlet.ServletResponse;
importjavax.servlet.http.HttpServletRequest;

publicclassCharacterFilterimplementsFilter{
privateStringcharset;
@Override
publicvoidinit(FilterConfigfilterConfig)throwsServletException{
charset=filterConfig.getInitParameter("charset");
}

@Override
publicvoiddoFilter(ServletRequestrequest,ServletResponseresponse,
FilterChainchain)throwsIOException,ServletException{
request.setCharacterEncoding(charset);
response.setCharacterEncoding(charset);
HttpServletRequestreq=(HttpServletRequest)request;
if(req.getSession().getAttribute("ip")==null){
req.getSession().setAttribute("ip",req.getRemoteAddr());
}
chain.doFilter(request,response);
}

@Override
publicvoiddestroy(){
}

}

LoginFilter.java(防止游客乱访问过滤器）

packagecn.hncu.filter;

importjava.io.IOException;

importjavax.servlet.Filter;
importjavax.servlet.FilterChain;
importjavax.servlet.FilterConfig;
importjavax.servlet.ServletException;
importjavax.servlet.ServletRequest;
importjavax.servlet.ServletResponse;
importjavax.servlet.http.HttpServletRequest;
importjavax.servlet.http.HttpServletResponse;

publicclassLoginFilterimplementsFilter{

@Override
publicvoidinit(FilterConfigfilterConfig)throwsServletException{

}

@Override
publicvoiddoFilter(ServletRequestrequest,ServletResponseresponse,
FilterChainchain)throwsIOException,ServletException{
HttpServletRequestreq=(HttpServletRequest)request;
if(req.getSession().getAttribute("user")==null){
((HttpServletResponse)response).sendRedirect(req.getContextPath()+"/index.jsp");
return;
}
chain.doFilter(request,response);
}

@Override
publicvoiddestroy(){
}

}

LoginServlet.java

packagecn.hncu.servlet;

importjava.io.IOException;
importjava.io.PrintWriter;

importjavax.servlet.ServletException;
importjavax.servlet.http.HttpServlet;
importjavax.servlet.http.HttpServletRequest;
importjavax.servlet.http.HttpServletResponse;

importcn.hncu.domain.User;

publicclassLoginServletextendsHttpServlet{


publicvoiddoGet(HttpServletRequestrequest,HttpServletResponseresponse)
throwsServletException,IOException{
doPost(request,response);
}
publicvoiddoPost(HttpServletRequestrequest,HttpServletResponseresponse)
throwsServletException,IOException{
Stringname=request.getParameter("name");
Useruser=(User)request.getSession().getAttribute("user");
if(user==null&&name!=null&&name.trim().length()>0){//封装User
user=newUser();
user.setName(name);
if(name.equals("admin")){
user.setAdmin(true);
}
}
request.getSession().setAttribute("user",user);
response.sendRedirect(request.getContextPath()+"/index.jsp");
}

}

ShowServlet.java

packagecn.hncu.servlet;

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

importjavax.servlet.ServletException;
importjavax.servlet.http.HttpServlet;
importjavax.servlet.http.HttpServletRequest;
importjavax.servlet.http.HttpServletResponse;
importjavax.servlet.http.HttpSession;

publicclassShowServletextendsHttpServlet{


publicvoiddoGet(HttpServletRequestrequest,HttpServletResponseresponse)
throwsServletException,IOException{
doPost(request,response);
}


publicvoiddoPost(HttpServletRequestrequest,HttpServletResponseresponse)
throwsServletException,IOException{
Map<String,HttpSession>onlines=(Map<String,HttpSession>)request.getServletContext().getAttribute("onlines");
List<Map<String,Object>>list=newArrayList<Map<String,Object>>();//吧Online封装成list
if(onlines!=null){
Iterator<HttpSession>it=onlines.values().iterator();
while(it.hasNext()){
HttpSessions=it.next();
Map<String,Object>map=newHashMap<String,Object>();
map.put("id",s.getId());
SimpleDateFormatsdf=newSimpleDateFormat("yyyy-MM-ddHH:mm:ss");
map.put("createTime",sdf.format(newDate(s.getCreationTime())));
map.put("lastAccessedTime",sdf.format(newDate(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

packagecn.hncu.servlet;

importjava.io.IOException;
importjava.io.PrintWriter;
importjava.util.Map;

importjavax.servlet.ServletException;
importjavax.servlet.http.HttpServlet;
importjavax.servlet.http.HttpServletRequest;
importjavax.servlet.http.HttpServletResponse;
importjavax.servlet.http.HttpSession;

publicclassKickOutServletextendsHttpServlet{


publicvoiddoGet(HttpServletRequestrequest,HttpServletResponseresponse)
throwsServletException,IOException{

doPost(request,response);
}
publicvoiddoPost(HttpServletRequestrequest,HttpServletResponseresponse)
throwsServletException,IOException{
Stringid=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

packagecn.hncu.servlet;

importjava.io.IOException;
importjava.io.PrintWriter;

importjavax.servlet.ServletException;
importjavax.servlet.http.HttpServlet;
importjavax.servlet.http.HttpServletRequest;
importjavax.servlet.http.HttpServletResponse;

publicclassLoginOutServletextendsHttpServlet{


publicvoiddoGet(HttpServletRequestrequest,HttpServletResponseresponse)
throwsServletException,IOException{

doPost(request,response);
}

publicvoiddoPost(HttpServletRequestrequest,HttpServletResponseresponse)
throwsServletException,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毛票票。

JavaEE在线人数管理系统

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