Web应用——驾培管理系统之登录功能（作者：小圣）

Web应用——驾培管理系统之登录功能（作者：小圣）

本节博文将向大家介绍本次驾培管理系统的登录功能。从创建一个对应数据表的bean开始，到界面填入参数，后台判断，传值，并且实现页面渲染，通过登录这一基础功能向大家展示这一流程，以供像我一样的初学者们学习。

笔者会把大概实现过程贴出来，有看不懂过程且需要项目源码的请戳：http://download.csdn.net/detail/xie_xiansheng/9486872，需要数据库表格的请留言。有些小细节没完善，有些代码冗余，初学请见谅！

首先来看结果图



首先是数据库所创建的用户表格t_user:



然后是数据库所有权限的表格t_function:



最后是数据库对应用户所拥有权限的表格t_user_function:



其次，是org.great.bean包下用户表t_user对应的UserBean

package org.great.bean;

public class UserBean {
private int user_id;
private int role_id;
private int driving_id;
private String user_lname;
private String user_pwd;
private String user_name;
private String user_sex;
private String user_status;
private String createtime;
private String tel;
private String driving_name;

public String getDriving_name() {
return driving_name;
}
public void setDriving_name(String drivingName) {
driving_name = drivingName;
}
public int getUser_id() {
return user_id;
}
public void setUser_id(int userId) {
user_id = userId;
}
public int getRole_id() {
return role_id;
}
public void setRole_id(int roleId) {
role_id = roleId;
}
public String getUser_lname() {
return user_lname;
}
public void setUser_lname(String userLname) {
user_lname = userLname;
}
public String getUser_pwd() {
return user_pwd;
}
public void setUser_pwd(String userPwd) {
user_pwd = userPwd;
}
public String getUser_name() {
return user_name;
}
public void setUser_name(String userName) {
user_name = userName;
}
public String getUser_sex() {
return user_sex;
}
public void setUser_sex(String userSex) {
user_sex = userSex;
}
public String getUser_status() {
return user_status;
}
public void setUser_status(String userStatus) {
user_status = userStatus;
}
public String getCreatetime() {
return createtime;
}
public void setCreatetime(String createtime) {
this.createtime = createtime;
}
public int getDriving_id() {
return driving_id;
}
public void setDriving_id(int drivingId) {
driving_id = drivingId;
}
public String getTel() {
return tel;
}
public void setTel(String tel) {
this.tel = tel;
}

}

权限表t_function对应的FuncBean:

package org.great.bean;

public class FuncBean {
private int func_id;
private int func_pid;
private String func_name;
private String func_url;
private String func_level;
private String func_tag;
public int getFunc_id() {
return func_id;
}
public void setFunc_id(int funcId) {
func_id = funcId;
}
public int getFunc_pid() {
return func_pid;
}
public void setFunc_pid(int funcPid) {
func_pid = funcPid;
}
public String getFunc_name() {
return func_name;
}
public void setFunc_name(String funcName) {
func_name = funcName;
}
public String getFunc_url() {
return func_url;
}
public void setFunc_url(String funcUrl) {
func_url = funcUrl;
}
public String getFunc_level() {
return func_level;
}
public void setFunc_level(String funcLevel) {
func_level = funcLevel;
}
public String getFunc_tag() {
return func_tag;
}
public void setFunc_tag(String funcTag) {
func_tag = funcTag;
}

}

然后是org.great.dao包下创建UserDao类，并且创建一个工厂类，控制单例，使之每次只实例化一个Dao
UserDao类：

public interface UserDao {
/**根据登录名查找用户信息*/
public UserBean findUser_ByLname(String lname);
}

DaoFactory类：

public class DaoFactory {
private static UserDao userDao = null;
private static FuncDao funcDao = null;

<span style="white-space:pre">	</span>public static FuncDao getFuncDao(){
<span style="white-space:pre">		</span>if(funcDao == null){
<span style="white-space:pre">			</span>funcDao = new FuncDaoImpl();
<span style="white-space:pre">		</span>}
<span style="white-space:pre">		</span>return funcDao;
<span style="white-space:pre">	</span>}

public static UserDao getUserDao(){
if(userDao == null){
userDao = new UserDaoImpl();
}
return userDao;
}

}

FuncDaoImpl实现类对应进行数据库查询操作：

private PreparedStatement pre =  null;
private ResultSet rs = null;

/** 获得权限表全部数据*/
public List<FuncBean> getFunc_ALL(int user_id){
List<FuncBean> list = new ArrayList<FuncBean>();
Connection conn = DBUtils.getConn();
String sql = "select f.func_id,f.func_pid,f.func_name,f.func_url,f.func_level from t_function f," +
"t_user_function rf where f.func_id = rf.func_id and rf.user_id = ?";
try {
pre = conn.prepareStatement(sql);
pre.setInt(1, user_id);
rs = pre.executeQuery();
while(rs.next()){
FuncBean funcBean = new FuncBean();
funcBean.setFunc_id(rs.getInt(1));
funcBean.setFunc_pid(rs.getInt(2));
funcBean.setFunc_name(rs.getString(3));
funcBean.setFunc_url(rs.getString(4));
funcBean.setFunc_level(rs.getString(5));
list.add(funcBean);
}
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally{
DBUtils.close(conn, pre, rs);
}

return list;
}

UserDaoImpl实现类对应的数据库查询操作：

private PreparedStatement pre = null;
private ResultSet rs = null;
public UserBean findUser_ByLname(String lname) {

Connection conn = DBUtils.getConn();
UserBean userBean = null;
String sql = "select user_id,role_id,user_lname,user_pwd,user_name,user_sex,user_status," +
"createtime,driving_id,tel from t_user where user_lname = ? and user_status!='D'" ;
try {
pre = conn.prepareStatement(sql);
pre.setString(1, lname);
rs = pre.executeQuery();

if(rs.next()){
userBean = new UserBean();
userBean.setUser_id(rs.getInt(1));
userBean.setRole_id(rs.getInt(2));
userBean.setUser_lname(rs.getString(3));
userBean.setUser_pwd(rs.getString(4));
userBean.setUser_name(rs.getString(5));
userBean.setUser_sex(rs.getString(6));
userBean.setUser_status(rs.getString(7));
userBean.setCreatetime(rs.getString(8));
userBean.setDriving_id(rs.getInt(9));
userBean.setTel(rs.getString(10));
}
} catch (SQLException e) {
e.printStackTrace();
} finally{
DBUtils.close(conn, pre, rs);
}
return userBean;

}

org.great.servlet包下的登录判断的Servlet类：LoginServlet

public class LoginServlet extends HttpServlet{
@Override
protected void service(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {

req.setCharacterEncoding("utf-8");
resp.setContentType("text/html;charset=utf-8");

String task = req.getParameter("task");
if(null == task){
req.setAttribute("msg", "请先登录！");
req.getRequestDispatcher("index.jsp").forward(req, resp);
}else if(task.equals("login")){
String userlname = req.getParameter("userlname");
String userpwd = req.getParameter("userpwd");
if("".equals(userlname)|| "".equals(userpwd)){
req.setAttribute("msg","用户名或密码不能为空！");
req.getRequestDispatcher("index.jsp").forward(req, resp);
}else {
System.out.println("task--111"+task);
UserDao userDao = DaoFactory.getUserDao();
//通过登录账户名获取用户信息
UserBean userBean = userDao.findUser_ByLname(userlname);
if(null==userBean){
req.setAttribute("msg", "用户名不存在");
req.getRequestDispatcher("index.jsp").forward(req, resp);
}else if(!userpwd.equals(userBean.getUser_pwd())){
req.setAttribute("msg", "密码输入错误");
req.getRequestDispatcher("index.jsp").forward(req, resp);
}else if(userBean.getRole_id()==3||userBean.getRole_id()==4){
req.setAttribute("msg", "抱歉，您没有权限登录");
req.getRequestDispatcher("index.jsp").forward(req, resp);
}else{
//列出权限->左侧导航栏
HttpSession session = req.getSession();
FuncDao funcDao = DaoFactory.getFuncDao();
List<FuncBean> funcBeans = funcDao.getFunc_ALL(userBean.getUser_id());
session.setAttribute("funcs", funcBeans);
session.setAttribute("Logindo", userBean);
session.setAttribute("funcDao", funcDao);
resp.sendRedirect("jsp/main/index.jsp");
}
}
}
}
}

WebRoot/index.jsp，项目初始页面(登录页面)

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">

<title>My JSP 'index.jsp' starting page</title>
<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
<link rel="stylesheet" type="text/css" href="<%=basePath%>/background/Style/skin.css" />
<script type="text/javascript" src="<%=basePath%>/jquery-2.1.4/jquery1.9.0.min.js"></script>
<script type="text/javascript" src="<%=basePath%>/easyvalidator2/js/validate.pack.js">
</script>
<link href="<%=basePath%>/easyvalidator2/css/validate.css" rel="stylesheet" type="text/css" />
</head>
<body>
<table width="100%">
<!-- 顶部部分 -->
<tr height="41"><td colspan="2" background="<%=basePath%>/background/Images/login_top_bg.gif"> </td></tr>
<!-- 主体部分 -->
<tr style="background:url(<%=basePath%>/background/Images/login_bg.jpg) repeat-x;" height="532">
<!-- 主体左部分 -->
<td id="left_cont">
<table width="100%" height="100%">
<tr height="155"><td colspan="2"> </td></tr>
<tr>
<td width="20%" rowspan="2"> </td>
<td width="60%">
<table width="100%">
<tr height="70"><td align="right"></td></tr>
<tr height="274">
<td valign="top" align="right">

</td>
</tr>
</table>
<td width="15%" rowspan="2"> </td>
</td>
</tr>
<tr><td colspan="2"> </td></tr>
</table>
</td>

<!-- 主体右部分 -->
<td id="right_cont">
<table height="100%">
<tr height="30%"><td colspan="3"> </td></tr>
<tr>
<td width="30%" rowspan="5"> </td>
<td valign="top" id="form">
<form action="login.do" method="post">
<table valign="top" width="50%">
<tr><td colspan="2"><h4 style="letter-spacing:1px;font-size:16px;">驾校管理后台</h4></td></tr>
<tr>
<td>用户名：</td>
<td>
<input type="text" name="userlname" value="" />
</td>
</tr>
<tr><td>密    码：</td><td><input type="password" name="userpwd" value="" />
<input type="hidden" name="task" value="login">
</td></tr>

<tr class="bt" align="center"><td> <input type="submit" value="登陆" /></td><td> <input type="reset" value="重填" /></td></tr>
</table>
</form>
</td>
<td rowspan="5"> </td>
</tr>
<tr><td colspan="3"> </td></tr>
</table>
</td>
</tr>
<!-- 底部部分 -->
<tr id="login_bot"><td colspan="2"><p>Copyright © 2015-2016 ChuanYi AX1510工作室</p></td></tr>
</table>
</body>
<script type="text/javascript">

var msg = "<%=request.getAttribute("msg")%>";
if(msg!="null"){
alert(msg);
}
</script>
</html>

登录成功后跳转的Jsp：WebRoot/jsp/main/index.jsp，它包含了三个jsp，使用了frame框架

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">

<title>My JSP 'index.jsp' starting page</title>

<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->

</head>

<frameset rows="64,*"  frameborder="no" border="0" framespacing="0">
<!--头部-->
<frame src="<%=basePath%>/jsp/main/top.jsp" name="top" noresize="noresize" frameborder="0"  scrolling="no" marginwidth="0" marginheight="0" />
<!--主体部分-->
<frameset cols="185,*">
<!--主体左部分-->
<frame src="<%=basePath%>/jsp/main/left.jsp" name="left" noresize="noresize" frameborder="0" scrolling="no" marginwidth="0" marginheight="0" />
<!--主体右部分-->
<frame src="<%=basePath%>/jsp/main/main.jsp" name="main" frameborder="0" scrolling="auto" marginwidth="0" marginheight="0" />
</frameset>
</html>

top.jsp

<%@ page language="java" import="java.util.*,org.great.bean.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">

<title>My JSP 'top.jsp' starting page</title>

<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<link rel="stylesheet" type="text/css" href="<%=basePath%>/background/Style/skin.css" />
<script type="text/javascript">
function logout() {
if(window.confirm('您确定要退出吗？')) {

top.location = 'user.do?task=logout';

}
}
</script>

</head>

<body>
<table cellpadding="0" width="100%" height="64" background="<%=basePath%>/background/Images/top_top_bg.gif">
<tr valign="top">
<td width="50%"><a href="javascript:void(0)"><img style="border:none" src="<%=basePath%>/background/Images/logo.png" /></a></td>
<td width="30%" style="padding-top:13px;font:15px Arial,SimSun,sans-serif;color:#FFF">尊敬的：<b style="color: red"><%=((UserBean)session.getAttribute("Logindo")).getUser_name()%></b> 您好，感谢登陆使用！</td>
<td style="padding-top:10px;" align="center"></td>
<td style="padding-top:10px;" align="center"><a href="javascript:void(0)"><img style="border:none" src="<%=basePath%>/background/Images/out.gif" onclick="logout();" /></td>
</tr>
</table>
</body>
<script type="text/javascript">

</script>
</html>

left.jsp

<%@ page language="java" import="java.util.*,org.great.bean.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">

<title>My JSP 'left.jsp' starting page</title>

<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
<script src="<%=basePath%>/background/Js/prototype.lite.js" type="text/javascript"></script>
<script src="<%=basePath%>/background/Js/moo.fx.js" type="text/javascript"></script>
<script src="<%=basePath%>/background/Js/moo.fx.pack.js" type="text/javascript"></script>
<link rel="stylesheet" type="text/css" href="<%=basePath%>/background/Style/skin.css" />
<script type="text/javascript">
window.onload = function () {
var contents = document.getElementsByClassName('content');
var toggles = document.getElementsByClassName('type');

var myAccordion = new fx.Accordion(
toggles, contents, {opacity: true, duration: 400}
);
myAccordion.showThisHideOpen(contents[0]);
for(var i=0; i<document .getElementsByTagName("a").length; i++){
var dl_a = document.getElementsByTagName("a")[i];
dl_a.onfocus=function(){
this.blur();
}
}
}
</script>
</head>

<body>
<table width="100%" height="280" border="0" cellpadding="0" cellspacing="0" bgcolor="#EEF2FB">
<tr>
<td width="182" valign="top">
<!-- 根据数据库的权限表获取到的权限来展开导航栏 -->
<%List<FuncBean> funcBeans =(List<FuncBean>)session.getAttribute("funcs");

%>

<div id="container">
<!-- 权限等级为1的为1级导航栏 -->
<%for(int i=0;i<funcBeans.size();i++){
if(funcBeans.get(i).getFunc_level().equals("1")){

%>
<h1 class="type"><a href="javascript:void(0)"><%=funcBeans.get(i).getFunc_name() %></a></h1>
<div class="content">
<table width="100%" border="0" cellspacing="0" cellpadding="0">
<tr>
<td><img src="<%=basePath%>/background/Images/menu-top-line.gif" width="182" height="5" /></td>
</tr>
</table>
<ul class="RM">
<!-- 权限等级为2的为2级导航栏 -->
<%for(int j=0;j<funcBeans.size();j++){
FuncBean funcBean =funcBeans.get(j);
if(funcBean.getFunc_level().equals("2")&&funcBean.getFunc_pid()==funcBeans.get(i).getFunc_id()){
%>
<li><a href="<%=funcBeans.get(j).getFunc_url()%>" target="main"><%=funcBeans.get(j).getFunc_name() %></a></li>
<%}} %>
</ul>
</div>
<% }}%>
</div>

</td>
</tr>
</table>
</body>
</html>

main.jsp

<%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<base href="<%=basePath%>">

<title>My JSP 'main.jsp' starting page</title>

<meta http-equiv="pragma" content="no-cache">
<meta http-equiv="cache-control" content="no-cache">
<meta http-equiv="expires" content="0">
<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="This is my page">
<!--
<link rel="stylesheet" type="text/css" href="styles.css">
-->
<link rel="stylesheet" type="text/css" href="<%=basePath%>/background/Style/skin.css" />
</head>

<body>
<table width="100%" border="0" cellpadding="0" cellspacing="0">
<!-- 头部开始 -->
<tr>
<td width="17" valign="top" background="<%=basePath%>/background/Images/mail_left_bg.gif">
<img src="<%=basePath%>/background/Images/left_top_right.gif" width="17" height="29" />
</td>
<td valign="top" background="<%=basePath%>/background/Images/content_bg.gif">
<table width="100%" height="31" border="0" cellpadding="0" cellspacing="0" background="<%=basePath%>/background/<%=basePath%>/background/Images/content_bg.gif">
<tr><td height="31"><div class="title" style="color: red">欢迎界面</div></td></tr>
</table>
</td>
<td width="16" valign="top" background="<%=basePath%>/background/Images/mail_right_bg.gif"><img src="<%=basePath%>/background/Images/nav_right_bg.gif" width="16" height="29" /></td>
</tr>
<!-- 中间部分开始 -->
<tr>
<!--第一行左边框-->
<td valign="middle" background="<%=basePath%>/background/Images/mail_left_bg.gif"> </td>
<!--第一行中间内容-->
<td valign="top" bgcolor="#F7F8F9">
<table width="100%" border="0" align="center" cellpadding="0" cellspacing="0">
<!-- 空白行-->
<tr><td colspan="2" valign="top"> </td><td> </td><td valign="top"> </td></tr>
<!--**********这里是内容**********-->
<!--**********这里是内容**********-->
<!--**********这里是内容**********-->
<!--**********这里是内容**********-->
<tr>
<!--左边内容-->
<td colspan="2" valign="top">
<h3 style="margin:0 0 10px 10px; color: blue">感谢您使用传一科技驾校管理程序</h3>
<img src="<%=basePath%>/background/Images/ts.gif" width="16" height="16" style="margin-left:10px;"> 提示：<br />
<p style="text-indent:20px;line-height:25px;margin-left:10px;font-size:15px;">您现在使用的是 传一科技开发的一套驾校管理系统！如果您有任何疑问请联系客户服务邮箱进行咨询！<br />    此程序是为您便捷管理驾校而使用！</p>
</td>
<!--间隔-->
<td width="7%"> </td>
<!--右边内容-->
<td width="40%" valign="top">
<table width="100%" height="150" border="0" cellpadding="0" cellspacing="0" style="border: 1px solid #CCCCCC;">
<tr>
<td width="7%" height="27" background="<%=basePath%>/background/Images/news_title_bg.gif">
<img src="<%=basePath%>/background/Images/news_title_bg.gif" width="2" height="27">
</td>
<td width="93%" background="<%=basePath%>/background/Images/news_title_bg.gif" class="left_bt">最新动态</td>
</tr>
<tr><td height="5" colspan="2"> </td></tr>
<tr>
<td height="100" valign="top" colspan="2" id="news">
<marquee direction="up" scrollamount="2" vspace="30px" width="400px" height="100px" onmouseout="this.start()" onmouseover="this.stop()">
<ul>
<li>厦门传一科技有限公司！</li>
<li>传一科技驾校管理系统！</li>
</ul>
</marquee>
</td>
</tr>
<tr><td height="5" colspan="2"> </td></tr>
</table>
</td>
</tr>
<tr height="20"><td colspan="2" valign="top"> </td><td> </td><td valign="top"> </td></tr>
<!--第二行-->
<tr>
<td colspan="2" valign="top">
<table width="100%" height="230" border="0" cellpadding="0" cellspacing="0" style="border: 1px solid #CCCCCC;">
<tr>
<td width="7%" background="<%=basePath%>/background/Images/news_title_bg.gif">
<img src="<%=basePath%>/background/Images/news_title_bg.gif" width="2" height="27">
</td>
<td width="93%" background="<%=basePath%>/background/Images/news_title_bg.gif" class="left_bt">最新动态</td>
</tr>
<tr>
<td height="186" valign="top" colspan="2"></td>
</tr>
<tr><td height="5" colspan="2"> </td></tr>
</table>
</td>
<td> </td>
<td valign="top">
<table width="100%" height="230" border="0" cellpadding="0" cellspacing="0" style="border: 1px solid #CCCCCC;">
<tr>
<td width="7%" background="<%=basePath%>/background/Images/news_title_bg.gif">
<img src="<%=basePath%>/background/Images/news_title_bg.gif" width="2" height="27">
</td>
<td width="93%" height="27" background="<%=basePath%>/background/Images/news_title_bg.gif" class="left_bt">最新动态</td>
</tr>
<tr><td height="186" valign="top"> </td><td height="102" valign="top"></td></tr>
<tr><td height="5" colspan="2"> </td></tr>
</table>
</td>
</tr>
<tr>
<td height="40" colspan="4">
<table width="100%" height="1" border="0" cellpadding="0" cellspacing="0" bgcolor="#CCCCCC">
<tr><td></td></tr>
</table>
</td>
</tr>
<tr>
<td width="2%"> </td>
<td width="51%" class="left_txt">
<img src="<%=basePath%>/background/Images/icon_mail.gif" width="16" height="11"> 客户服务邮箱：870873201@qq.com<br />
<img src="<%=basePath%>/background/Images/icon_phone.gif" width="17" height="14"> 官方网站：<a href="http://my.csdn.net/xie_xiansheng" target="_blank">作者博客</a>
</td>
<td> </td><td> </td>
</tr>
</table>
</td>
<td background="<%=basePath%>/background/Images/mail_right_bg.gif"> </td>
</tr>
<!-- 底部部分 -->
<tr>
<td valign="bottom" background="<%=basePath%>/background/Images/mail_left_bg.gif">
<img src="<%=basePath%>/background/Images/buttom_left.gif" width="17" height="17" />
</td>
<td background="<%=basePath%>/background/Images/buttom_bgs.gif">
<img src="<%=basePath%>/background/Images/buttom_bgs.gif" width="17" height="17">
</td>
<td valign="bottom" background="<%=basePath%>/background/Images/mail_right_bg.gif">
<img src="<%=basePath%>/background/Images/buttom_right.gif" width="16" height="17" />
</td>
</tr>
</table>
</body>
</html>

最后是过滤器类：org.great.filter下的LoginFilter

public class LoginFilter implements Filter{

public void doFilter(ServletRequest sreq, ServletResponse sresp,
FilterChain chain) throws IOException, ServletException {
HttpServletRequest req = (HttpServletRequest)sreq;
HttpServletResponse resp = (HttpServletResponse) sresp;

HttpSession session = req.getSession();
String path = req.getServletPath();
String apath = req.getContextPath();
//如果是路径以/index.jsp  /background(图片存放文件) /login.do 开始的直接放过，其他的拦截判断
if(!path.startsWith("/index.jsp")&&!path.startsWith("/background")&&!path.startsWith("/login.do")){
Object object = session.getAttribute("Logindo");
if(object ==null){
resp.sendRedirect(apath+"/index.jsp");
}else{
chain.doFilter(req, resp);
}
}else{
chain.doFilter(req, resp);
}

}

public void init(FilterConfig arg0) throws ServletException {

}

public void destroy() {

}

}

并且在web.xml进行配置：

<servlet>
<servlet-name>loginServlet</servlet-name>
<servlet-class>org.great.servlet.LoginServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>loginServlet</servlet-name>
<url-pattern>/login.do</url-pattern>
</servlet-mapping>

<filter>
<filter-name>loginFilter</filter-name>
<filter-class>org.great.filter.LoginFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>loginFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>