JavaEE——在线人管理系统（显示在线人数、在线人详细信息、管理员踢人）

来源：互联网发布：制作身份证图片软件编辑：程序博客网时间：2024/04/28 05:52

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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