JavaEE在线人数管理系统 JavaEE在线人数管理系统
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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> 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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