web实验报告——会话跟踪使用程序
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实验
八
会话跟踪实用程序
一、实验目的
通过实验掌握下列知识：
1
、
理解动态网页中会话跟踪的实现基础；
2
、
能使用会话跟踪实现购物车程序。
二、实验内容及步骤
1
、购物车程序基础练习
1
）将书中购物车程序实例源代码，配置于
tomcat
服务器中；
2
）运行该程序，查看运行效果，并将运行流程与效果，记录在实验报告中；
分析该程序采取的线程安全措施，并记录在实验报告中。
购物车程序实例源代码：
session.rar
运行界面：
TechBooksPage
：
OrderPage：
ShowSession
：
2
、购物车程序改进练习
1
）为书中的基础程序增加登录页面（
login.jsp
），并增加登录判断页面（
LoginCheck.java
）
,
若用户名为
bookstore
，密码为
123456
，则登录成功，直接跳转显示
KidsBooksPage
，否则返回登录页面重新登录；
2
）若登录成功，则在登录判断页面（
LoginCheck.java
）中增加代码：
session.setAttribute(“loginUser”, true); 用以标志登录用户；
3
）购书页面（
KidsBooksPage
、
TechBooksPage
）与订单页面（
OrderPage
）必须要登录用户才能访问，未登录用户需跳转到登录页面进行登录；
4
）若登录用户再次访问登录页面（
login.jsp
），则无须再次登录，直接跳转显示
KidsBooksPage
。
源代码：
login.jsp:
<%@
page language="java" contentType="text/html; charset=gb2312"
pageEncoding="gb2312"%>
<!
DOCTYPE
html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<
html
>
<
head
>
<
meta
http-equiv="Content-Type" content="text/html; charset=gb2312">
<
title
>
用户登录界面
</
title
>
</
head
>
<
body
>
<%
//
使用内置对象
request
获取
loginUser
的
session
的值，若为空则停留在登陆界
面，
//
若存在
session
值就直接跳转到
KidsBooksPage
页面
Boolean flag1;
HttpSession loginSession = request.getSession();
flag1 = (Boolean)loginSession.getAttribute(
"loginUser"
);
if
(flag1==
null
|| flag1==
false
)
{
%>
<
br
>
<
br
>
<
br
>
<
div
align = "center">
<
h1
>
用户登录
</
h1
>
</
div
>
<
form
action= "LoginCheck">
<
table
align="center">
<
tr
>
<
td
>
用户名
</
td
>
<
td
><
input
name = "userName"></td>
</
tr
>
<
tr
>
<
td
>
密码
</
td
>
<
td
><
input
type="password" name = "userPwd"></td>
</
tr
>
<
tr
>
<
td
colspan = "2" align = "center"><input type="submit" value = "
提交
"
></
td
>
</
tr
>
</
table
>
</
form
>
<%
}
else
{
%>
<
jsp:forward
page= "KidsBooksPage" />
<%
}
%>
</
body
>
</
html
>
LoginCheck.java
package
session;
import
java.io.IOException;
import
javax.servlet.ServletException;
import
javax.servlet.http.Cookie;
import
javax.servlet.http.HttpServlet;
import
javax.servlet.http.HttpServletRequest;
import
javax.servlet.http.HttpServletResponse;
import
javax.servlet.http.HttpSession;
/**
*
Servlet
implementation
class
LoginCheck
*/
public
class
LoginCheck
extends
HttpServlet {
private
static
final
long
serialVersionUID
= 1L;
/**
*
@see
HttpServlet#HttpServlet()
*/
public
LoginCheck() {
super
();
//
TODO
Auto-generated constructor stub
}
/**
*
@see
HttpServlet#doGet(HttpServletRequest
request,
HttpServletResponse
response)
*/
protected
void
doGet(HttpServletRequest request, HttpServletResponse response)
throws
ServletException, IOException {
//
TODO
Auto-generated method stub
HttpSession session = request.getSession();
String name = request.getParameter(
"userName"
);
String pwd = request.getParameter(
"userPwd"
);
if
(name.equals(
"bookstore"
) && pwd.equals(
"123456"
))
{
session.setAttribute(
"loginUser"
,
true
);
response.sendRedirect(
"KidsBooksPage"
);
}
else
{
response.sendRedirect(
"login.jsp"
);
}
}
/**
*
@see
HttpServlet#doPost(HttpServletRequest
request,
HttpServletResponse
response)
*/
protected
void
doPost(HttpServletRequest request, HttpServletResponse response)
throws
ServletException, IOException {
//
TODO
Auto-generated method stub
}
}
运行结果：
3
、购物车程序改进练习
2
（选做）
1
）为以上程序增加注销功能，在购书页面（
KidsBooksPage
、
TechBooksPage
）与订单页面（
OrderPage
）中增加注销按钮；
2
）按下注销按钮后，交由
Logout.java
页面进行处理：
session.invalidate(); response.sendRedirect(“../login.jsp”);
源代码：
package
session;
import
java.io.*;
import
javax.servlet.*;
import
javax.servlet.http.*;
import
java.util.*;
public
abstract
class
CatalogPage
extends
HttpServlet {
private
Item[]
items
;
private
String[]
itemIDs
;
private
String
title
;
/**
Given
an
array
of
item
IDs,
look
them
up
in
the
*
Catalog
and
put
their
corresponding
Item
entry
*
into
the
items
array.
The
Item
contains
a
short
*
description,
a
long
description,
and
a
price,
*
using
the
item
ID
as
the
unique
key.
*
<P>
*
Servlets
that
extend
CatalogPage
<B>
must
</B>
call
*
this
method
(usually
from
init
)
before
the
servlet
*
is
accessed.
*/
protected
void
setItems(String[] itemIDs) {
this
.
itemIDs
= itemIDs;
items
=
new
Item[itemIDs.
length
];
for
(
int
i=0; i<
items
.length; i++) {
items
[i] = Catalog.getItem(itemIDs[i]);
}
}
/**
Sets
the
page
title,
which
is
displayed
in
*
an
H1
heading
in
resultant
page.
*
<P>
*
Servlets
that
extend
CatalogPage
<B>
must
</B>
call
*
this
method
(usually
from
init
)
before
the
servlet
*
is
accessed.
*/
protected
void
setTitle(String title) {
this
.
title
= title;
}
/**
First
display
title,
then,
for
each
catalog
item,
*
put
its
short
description
in
a
level
-
two
(H2)
heading
*
with
the
price
in
parentheses
and
long
description
*
below.
Below
each
entry,
put
an
order
button
*
that
submits
info
to
the
OrderPage
servlet
for
*
the
associated
catalog
entry.
*
<P>
*
To
see
the
HTML
that
results
from
this
method,
do
*
"View
Source"
on
KidsBooksPage
or
TechBooksPage,
two
*
concrete
classes
that
extend
this
abstract
class.
*/
public
void
doGet(HttpServletRequest request,
HttpServletResponse response)
throws
ServletException, IOException {
response.setContentType(
"text/html"
);
response.setCharacterEncoding(
"gb2312"
);
//
获取名为
loginUser
的
session
，若为
true,
就显示该页面，否则返回
login.jsp
页面
Boolean flag;
HttpSession session = request.getSession();
synchronized
(session) {
flag = (Boolean)session.getAttribute(
"loginUser"
);
if
(flag==
null
|| flag ==
false
)
{
response.sendRedirect(
"login.jsp"
);
}
else
{
if
(
items
==
null
) {
response.sendError(response.
SC_NOT_FOUND
,
"Missing Items."
);
return
;
}
PrintWriter out = response.getWriter();
out.println(ServletUtilities.headWithTitle(
title
) +
"<BODY BGCOLOR=/"#FDF5E6/">/n"
+
"<H1 ALIGN=/"CENTER/">"
+
title
+
"</H1>"
);
Item item;
for
(
int
i=0; i<
items
.length; i++) {
out.println(
"<HR>"
);
item =
items
[i];
// Show error message if subclass lists item ID
// that's not in the catalog.
if
(item ==
null
) {
out.println(
"<FONT COLOR=/"RED/">"
+
"Unknown item ID "
+
itemIDs
[i] +
"</FONT>"
);
}
else
{
out.println();
String formURL =
"OrderPage"
;
// Pass URLs that reference own site through encodeURL.
formURL = response.encodeURL(formURL);
out.println
(
"<FORM ACTION=/""
+ formURL +
"/">/n"
+
"<INPUT TYPE=/"HIDDEN/" NAME=/"itemID/" "
+
" VALUE=/""
+ item.getItemID() +
"/">/n"
+
"<H2>"
+ item.getShortDescription() +
" ($"
+ item.getCost() +
")</H2>/n"
+
item.getLongDescription() +
"/n"
+
"<P>/n<CENTER>/n"
+
"<INPUT TYPE=/"SUBMIT/" "
+
"VALUE=/"Add to Shopping Cart/">/n"
+
"</CENTER>/n<P>/n</FORM>"
);
String formURL2 =
"Logout"
;
formURL2 = response.encodeURL(formURL2);
out.println(
"<FORM ACTION=/""
+ formURL2 +
"/">/n"
+
"<INPUT TYPE=/"SUBMIT/" "
+
"VALUE=/"
注销
/">/n"
+
"</CENTER>/n<P>/n</FORM>"
);
}
out.println(
"<HR>/n</BODY></HTML>"
);
}
}
}
}
/**
POST
and
GET
requests
handled
identically.
*/
public
void
doPost(HttpServletRequest request,
HttpServletResponse response)
throws
ServletException, IOException {
doGet(request, response);
}
}
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