JavaWeb-网站在线用户信息、网站访问量以及管理踢出用户实例（2）-阿里云开发者社区

LogOutServlet

用于用户的安全退出！

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 LogOutServlet 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 {
        //用户安全退出很简单，我们在服务器端移除用户的session就可以了
        request.getSession().invalidate();
        response.sendRedirect(request.getContextPath()+"/index.jsp");
    }
}

ShowServlet

显示所有用户信息时的servlet，需要把信息全部封装到request这个容器中，再转发到前台jsp显示的页面。

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 java.util.Map.Entry;
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>) getServletContext().getAttribute("onLines"); 
        List<Map<String, Object>> lists = new ArrayList<Map<String,Object>>();
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        //遍历onlines，针对每个session对象封装一个map(信息包含:name,createTime,lastAccessTime,ip)，把该map添加到list当中
        Iterator<Entry<String, HttpSession>> it = onLines.entrySet().iterator();
        while(it.hasNext()){
            Entry<String, HttpSession> en = it.next();
            Map<String, Object> m = new HashMap<String, Object>();
            m.put("id", en.getValue().getId() );
            m.put("user", en.getValue().getAttribute("user"));
            String creationTime = sdf.format(new Date(en.getValue().getCreationTime()));
            m.put("creationTime", creationTime);
            String lastAccessTime = sdf.format( new Date(en.getValue().getLastAccessedTime()) );
            m.put("lastAccessTime", lastAccessTime);
             //注意,该ip数据是在CharsetFilter中封装的
            m.put("ip", en.getValue().getAttribute("ip"));
            lists.add(m);
        }
        request.setAttribute("onLines", lists);
        request.getRequestDispatcher("/jsps/show.jsp").forward(request, response);
    }
}

show.jsp

前台在线用户的显示页面，会员和管理员看到的页面是不同的，管理员可以踢人。

<%@ 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>在线人信息管理</title>
    <style type="text/css">
       table{
          border: 1px solid red;
          border-collapse: collapse;/*设置单线-线合并*/
          width: 80%;
       }
       td{
          border: 1px solid red;
          padding:3px;
       }
       .header{
         background: gray;
       }
    </style>
  </head>
  <body>
    <h2>以下是所有在线用户信息</h2>   
    <table>
       <tr class="header" >
          <td>姓名</td>  <td>上线时间</td>  <td>最后访问时间</td> <td>IP</td> <td>操作</td>
       </tr>
       <c:forEach items="${requestScope.onLines}" var="map">
        <tr>
            <td>
                <c:if test="${empty map.user}" var="boo">
                    游客                  
                </c:if>
                <c:if test="${!boo}">
                    ${map.user.name}
                </c:if>
            </td>
            <td>${map.creationTime}  </td>
            <td>${map.lastAccessTime}</td>
            <td>${map.ip }           </td>
            <td>
                <c:if test="${!boo&&user.admin}">
                     <a href="<c:url value='/servlet/KickOutServlet?id=${map.id}'/> " >踢出${map.user.name}</a>
                </c:if>
            </td>
        </tr>
       </c:forEach>
    </table>
       <br/>网站访问量:${count}
  </body>
</html>

KickOutServlet

管理踢人时请求的servlet，在这里我们把被踢的人的session从服务器端移除就可以了。但是注意防范一下，那个被踢者是否已经被踢走了、

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 {
        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        String id = request.getParameter("id");
        Map<String, HttpSession> onLines = (Map<String, HttpSession>) getServletContext().getAttribute("onLines");
        if(onLines.containsKey(id)){
            HttpSession session = onLines.get(id);//得到该session
            session.invalidate();//移除该session
            out.println("该用户已被踢出!");
        }else{
            out.println("该用户已经不存在!");
        }
    }
}

user

JavaBean,在这里，我就是简单的封装了一个JavaBean使用了。我们的知识点并不是这里。

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 {
        response.setContentType("text/html");
        PrintWriter out = response.getWriter();
        String id = request.getParameter("id");
        Map<String, HttpSession> onLines = (Map<String, HttpSession>) getServletContext().getAttribute("onLines");
        if(onLines.containsKey(id)){
            HttpSession session = onLines.get(id);//得到该session
            session.invalidate();//移除该session
            out.println("该用户已被踢出!");
        }else{
            out.println("该用户已经不存在!");
        }
    }
}

web.xml

注意啊！无论是servlet还是监听器，过滤器！一定要记得配置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> 
  <listener>
    <listener-class>cn.hncu.listeners.MyServletContextListener</listener-class>
  </listener>
  <listener>
    <listener-class>cn.hncu.listeners.MySessionListener</listener-class>
  </listener>
  <servlet>
    <servlet-name>LoginServlet</servlet-name>
    <servlet-class>cn.hncu.servlet.LoginServlet</servlet-class>
  </servlet>
  <servlet>
    <servlet-name>LogOutServlet</servlet-name>
    <servlet-class>cn.hncu.servlet.LogOutServlet</servlet-class>
  </servlet>
  <servlet>
    <servlet-name>ShowServlet</servlet-name>
    <servlet-class>cn.hncu.servlet.ShowServlet</servlet-class>
  </servlet>
  <servlet>
    <servlet-name>KickOutServlet</servlet-name>
    <servlet-class>cn.hncu.servlet.KickOutServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>LoginServlet</servlet-name>
    <url-pattern>/LoginServlet</url-pattern>
  </servlet-mapping>
  <servlet-mapping>
    <servlet-name>LogOutServlet</servlet-name>
    <url-pattern>/servlet/LogOutServlet</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>
  <filter>
    <filter-name>charset</filter-name>
    <filter-class>cn.hncu.filter.CharsetFilter</filter-class>
  </filter>
  <filter>
    <filter-name>login</filter-name>
    <filter-class>cn.hncu.filter.LoginFilter</filter-class>
  </filter>
  <filter-mapping>
    <filter-name>login</filter-name>
    <url-pattern>/servlet/*</url-pattern>
    <url-pattern>/jsps/*</url-pattern>
  </filter-mapping>
  <filter-mapping>
    <filter-name>charset</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
</web-app>

演示结果：

登录之前显示的主页:

未登录的时候，是无法进入显示所有在线用户的，用过滤器拦截了。

登录之后显示的主页:

管理员登录后显示的在线人信息

如果不是管理员登录后，最后的操作时不会显示的。

完整的项目链接：

https://github.com/chenhaoxiang/Java/tree/master/myOnlinesWeb2

希望本篇博客对大家有一点用(^-^)

JavaWeb-网站在线用户信息、网站访问量以及管理踢出用户实例（2）

LogOutServlet

ShowServlet

show.jsp

KickOutServlet

user

web.xml

登录之前显示的主页:

登录之后显示的主页:

管理员登录后显示的在线人信息

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