标签：后台控制学习
登陆页面<%@ page language="java" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<body>
<form
action="${pageContext.request.contextPath}/LoginServlet"
method="post">
用户名：<input type="text" name="username"/>
<input type="submit" value="登录"/>
</form>
</body>
</html>
<%@ page language="java" pageEncoding="UTF-8"%>
<%@ page import="cn.vote.domain.*" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<body>
欢迎${!empty username?username:‘游客‘}光临
</body>
</html>
<%@ 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>后台操作</caption>
<tr>
<th>用户名</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>
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;
//监听器
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")){
//取得该用户对应的HttpSession
HttpSession session = se.getSession();
//取得该web应用的SerlvetContext对象
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) {
}
}
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();
//将用户名绑定到HttpSession中,事件触发
session.setAttribute("username",username);
response.sendRedirect(request.getContextPath()+"/welcome.jsp");
}
}
}
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)) {
// 解码
String username = request.getParameter("username");
byte[] buf = username.getBytes("ISO8859-1");
username = new String(buf, "UTF-8");
// 从ServletContext中取得Map对象
Map<String, HttpSession> map = (Map<String, HttpSession>) this.getServletContext().getAttribute("map");
// 根据用户名查找对应的HttpSession
HttpSession session = map.get(username);
// 将该用户名从Map中移除
map.remove(username);
// 强行销毁该HttpSession
session.invalidate();
// 重写向到manager.jsp
response.sendRedirect(request.getContextPath() + "/manager.jsp");
}
}
}
<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>标签：后台控制学习
原文地址：http://blog.51cto.com/357712148/2105857
