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Système de gestion du nombre d'utilisateurs en ligne JavaEE en ligne

Ce blogue est une synthèse des technologies filter, listener et servlet, et réalise des fonctions simples telles que l'affichage du nombre d'utilisateurs en ligne, des détails des utilisateurs en ligne et la fonction de kick des administrateurs

Voici le code détaillé

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>Informations des utilisateurs en ligne</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>Nom</th>
   <th>Heure de connexion</th>
   <th>Heure du dernier accès</th>
   <th>ip</th>
   <th>Opération</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 }">
      Visiteur
    </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}"/>' Éjecter </a>
     </c:if>
    </c:if>
   </td>
  </tr>
  </c:forEach>
 </table>
</body>
</html>

User.java (valeur objet)

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 ", utilisateur [name=" + name + ", admin=" + admin + "]";
 }
}

MySessionListener.java(écouteur)

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>());//Synchroniser la map
   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) {//Encapsulation de 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>>();//Encapsuler Online en liste
  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});
 }
}

Voici la totalité du contenu de cet article, j'espère qu'il vous sera utile dans vos études, et j'espère que vous soutiendrez également le tutoriel de cri.

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