後臺控制學習
阿新 • • 發佈：2018-04-20
後臺控制學習登陸頁面
<%@ page language="java" pageEncoding="UTF-8"%> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <body> <form action="${pageContext.request.contextPath}/LoginServlet" method="post"> 用戶名：<input type="text" name="username"/> <input type="submit" value="登錄"/> </form> </body> </html>
顯示頁面
<%@ page language="java" pageEncoding="UTF-8"%>
<%@ page import="cn.vote.domain.*" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<body>
歡迎${!empty username?username:‘遊客‘}光臨
</body>
</html>
管理員頁面
<%@ page language="java" 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> <body> <table border="1" align="center"> <caption>後臺操作</caption> <tr> <th>用戶名</th> <th>操作</th> </tr> <c:forEach var="entry" items="${map}"> <tr> <td>${entry.key}</td> <td> <c:url var="myURL" value="/KickServlet"> <c:param name="username" value="${entry.key}"/> </c:url> <a href="${myURL}" style="text-decoration:none"> 踢人 </a> </td> </tr> </c:forEach> </table> </body> </html>
java代碼
監聽代碼
package cn.xijie.listener; import java.util.HashMap; import java.util.Map; import javax.servlet.ServletContext; import javax.servlet.http.HttpSession; import javax.servlet.http.HttpSessionAttributeListener; import javax.servlet.http.HttpSessionBindingEvent; //監聽器 public class KickListener implements HttpSessionAttributeListener { public void attributeAdded(HttpSessionBindingEvent se) { String name = se.getName();//name="username" String value = (String) se.getValue();//value="jack" if(name.equals("username")){ //取得該用戶對應的HttpSession HttpSession session = se.getSession(); //取得該web應用的SerlvetContext對象 ServletContext context = session.getServletContext(); Map<String,HttpSession> map = (Map<String, HttpSession>) context.getAttribute("map"); if(map==null){ map = new HashMap<String,HttpSession>(); } map.put(value,session); context.setAttribute("map",map); } } public void attributeRemoved(HttpSessionBindingEvent se) { } public void attributeReplaced(HttpSessionBindingEvent se) { } }
登陸代碼
package cn.xijie.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 javax.servlet.http.HttpSession;
public class LoginServlet extends HttpServlet {
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String username = request.getParameter("username");
if(username != null && username.trim().length() > 0)
{
HttpSession session = request.getSession();
//將用戶名綁定到HttpSession中,事件觸發
session.setAttribute("username",username);
response.sendRedirect(request.getContextPath()+"/welcome.jsp");
}
}
}
控制代碼
package cn.xijie.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 java.util.Map;
import javax.servlet.http.HttpSession;
public class KickServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String ip = request.getRemoteAddr();
if ("127.0.0.1".equals(ip)) {
// 解碼
String username = request.getParameter("username");
byte[] buf = username.getBytes("ISO8859-1");
username = new String(buf, "UTF-8");
// 從ServletContext中取得Map對象
Map<String, HttpSession> map = (Map<String, HttpSession>) this.getServletContext().getAttribute("map");
// 根據用戶名查找對應的HttpSession
HttpSession session = map.get(username);
// 將該用戶名從Map中移除
map.remove(username);
// 強行銷毀該HttpSession
session.invalidate();
// 重寫向到manager.jsp
response.sendRedirect(request.getContextPath() + "/manager.jsp");
}
}
}
wenb.xml
<servlet>
<servlet-name>LoginServlet</servlet-name>
<servlet-class>cn.xijie.servlet.LoginServlet</servlet-class>
</servlet>
<servlet>
<servlet-name>KickServlet</servlet-name>
<servlet-class>cn.xijie.servlet.KickServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>LoginServlet</servlet-name>
<url-pattern>/LoginServlet</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>KickServlet</servlet-name>
<url-pattern>/KickServlet</url-pattern>
</servlet-mapping>後臺控制學習