JavaEE在线人数管理系统
发布时间：2020-12-05 05:27:51 所属栏目：Java 来源：互联网
导读：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
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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>) 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() {
}
}
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