外文文献—从经典ASP到ASPNET

附录Ⅰ

英文文献翻译

Moving from Classic ASP to

ABSTRACT

is

Microsoft

new

offering

for

Web

application

development,

innovation

within

have resulted in significant industry popularity for this product. Consequently there is

an

increased

need

for

education.

The

Web

Application

Development

is

a

third

year

undergraduate course. To meet the demands of both industry and students, we have changed the

focus of this course from Classic ASP to . This paper reports this move. The significant

features of and the motivations for this move are discussed. The process, the problems

encountered, and some helpful online learning resources are described.

Key words: Web Application Development, Classic ASP, , Move,

1. INTRODUCTION

is

not

just

a

new

version

of

ASP.

It

provides

innovation

for

moving

Windows

applications to Web applications. Web services and the .NET framework have made the vision of

the Web as the next generation computing platform a reality. With server controls, Web forms and

“code

-

behind”,

we

can

develop

a

Web

application

by

using

a

complete

object

-oriented

programming (OOP) model. This increases the popularity of in industry. The industry

project is the final course of the Bachelor of Computing

Systems

(BCS) degree at UNITEC, in

which

students

undertake

a

real- world

project.

We

have

observed

a

rapid

growth

of

related industry projects in our school.

The Web Application Development (WAD) paper is a third year undergraduate course. It was

originally offered using ASP 2.0 and ColdFusion. To meet the demands from both industry and

students, we have changed the course content to cover , Visual ()

and ColdFusion. This change commenced with the first semester of 2003.

This

paper

will

examine

the

features

of

and

explain

why

these

are

unique.

The

motivations for moving to are discussed by analyzing the current situation of

related to industry projects in our school, analyzing the results of short surveys on students, and

analyzing whether is a better tool for teaching. Problems encountered during the move

are also discussed and some of the learning resources are presented. It is anticipated that these will

be helpful for teachers who intend to introduce .

2. WHAT MAKES SPECIAL?

There are many articles on the Internet discussing the advantages of over Classic

Active

Server

Pages

(ASP),

such

as

that

introduces

an

integrated

development

environment (IDE), a single development library for all types of applications, compiled as well as

strongly typed code, and a true OO approach to Web application development (Goodyear, 2002,

Bloom, 2002).

Traditionally,

we

have

three

versions

of

ASP

(ASP

1.0,

ASP

2.0

and

ASP

3.0),

which

are

called

Classic

ASP.

Although

each

version

provides

certain

new

features

to

overcome

the

shortcomings of its predecessors, these versions of ASP follow the same working model and share

many

limitations.

Their

successor

supports

complete

new

working

model

while

preserving

the

traditional

working

model

and

provides

innovative

techniques

to

overcome

the

limitations of Classic ASP.

2.1. Architecture

enhances

and

extends

the

Windows

DNA

(Windows

Distributed

interNet

Application). The windows DNA specification is a methodology for building n-tier applications

using

Microsoft

(DCOM/COM)

technologies.

Breaking

applications

into

functional

pieces

and

deploying these across a network is a strategy to make better use of organizational resources. This

needs

a

well-planned

architecture.

In

the

past,

usually

it

was

the

windows

DNA.

DCOM

communication

normally

has

problems

with

firewalls

and

proxy

servers.

This

means

Windows

DNA

usually

only

works

well

within

an

intranet,

not

on

the

Internet.

DCOM/

COM

also

need

registry entries.

makes the process of creating and integrating Web Services easier, which can be

used in a similar manner to the Windows DNA. Here DCOM/COM is no longer involved. HTTP

(as

channels),

SOAP

(as

formatters)

and

XML

are

used

for

communication

and

data-transfer

between

distributed

components.

This

overcomes

the

problem

of

communicating

across

the

Internet

and

across

corporate

firewalls

without

resorting

to

proprietary

solutions

that

require

additional

communications

ports

to

be

opened

to

external

access.

In

addition,

URI

(uniform

resource

identifier)

and

UDDI

(Universal

Description

Discovery

and

Integration)

are

used

for

remote components references instead of registry entries.

2.2. Development

integrates

seamlessly

with

IDE.

includes

built-in

support

for

creating and modifying content. This unifies the ASP/VB programming models for the developers.

Instead of opening multiple IDEs (as with Classic ASP platform), developers can open a single

IDE and do all their work from a clean, consistent interface. is equipped with powerful

debugging environment. This means that the powerful debugger for Windows applications is now

available to debug Web applications as well.

enables

programmers

to

take

advantage

of

the

OOP

model,

for

example,

code

sharing. Under OOP model, one of the most common ways to achieve code sharing is inheritance,

which

is

not

available

in

Classic

ASP.

Since

complete

OO

features

are

supported

in

,

developers

can

transfer

their

OO

design

smoothly

into

code,

enabling

a

software

company to keep their Windows application development styles, with which they are familiar, in

Web

application

development;

and

also

they

can

convert

their

Windows

applications

into

Web

applications without major modifications.

’s improved state maintenance features enable us to provide users with Web applications

that are richer and faster than Classis ASP (Olges,2002). supports advanced session state

management.

There

are

two

major

problems

with

session

management

in

Classic

ASP:

session

objects are stored in the Web server memory and session IDs are stored on the client computers as

cookies. These prevent session management from being efficiently implemented. solves

the

se problems in two ways: it provides a “cookieless” option for session objects so that a session

ID can be passed via URL; it provides three different session modes (in process, state server, and

SQL Server), so that a session object can either be stored on the Web server, a remote server or a

database.

3. THE MOTIV

ATIONS FOR MOVING

3.1. The industry motivation

I’ve

checked

almost

all

the

industry

projects

in

our

school

for

three

semesters

on

whether

they are WAD related, if yes, then what tools they have used. Table 1 shows a brief summary of

the these three semesters, the total ASP/ projects are increasing, but slowly.

However the Classic ASP projects are dropping quickly and the projects are increasing

rapidly (in the speed of more than 12% per semester). This gives us an idea that

is preferred over Classic ASP in industry especially given that is only

officially

first

released

in

2002.

Our

student’s

feedbacks

from

their

industry

communication

confirm

this

view.

A

huge

number

of

articles

on

the

Internet

also

support

this

view.

This

encourages us to drop Classic ASP and move to in our W

AD course. Higher education

has over years recognized that it is a service industry and has to revaluate their approach in the

industry by placing greater emphasis on meeting the expectations and needs of their stakeholders

(Nair, 2002).

3.2. The student motivation

The students demand . When students enroll in our WAD course, most of them are

aiming to become a professional software developer. As a matter of fact, some of them already are

software developers, or they were software developers and are seeking to return to the workplace.

Techniques highly demanded in workplace are of great interest to them.

A short survey has been given to past students and current students respectively. For the past

students,

among

the

11

responses,

100%

students

still

want

to

learn

;

and

if

they

are

given choice, 82% students prefer to learn rather than Classic ASP, 18% students like to

learn both. These answers are also supported by comments, such as “I would prefer to know the

technology that the industry requires me to work with”, “I would like to work in future as a W

AD

professional and I think would be useful in t

his field.” For the current students, among

the 16 responses, 75% students prefer to learn rather than Classic ASP. However, 25%

students answered no idea. This could be due to that they lack of knowledge of Classic ASP. This

survey is done after 6 weeks of teaching.

3.3. The pedagogical motivation

Pedagogically speaking, a good tool for industry is not necessarily a good tool for teaching.

Is a better tool for teaching than Classic ASP?

provides much richer language features than Classic ASP. We often have options to

perform certain tasks. A key benefit of is that there exists a more gradual transition in

programming

models

from

simple

to

powerful,

or

from

easy

to

difficult.

Although

supports

OOP

model,

you

don’t

hav

e

to

program

by

using

that

model.

A

Web

form

without

“code

-

behind” will work perfectly. An web page in complete Classic ASP model will

still work. Although is integrated with , we are not limited to use . A

notepad and a FTP client with a pre-created Web application directory also allow us to develop a

reasonably large application. With , we can either develop a large distributed

application

with

numbers

of

Web

services

and

consumers,

or

develop

a

single

simple

Web

application. Therefore, provides sufficient room for us to organize course materials at a

suitable level for the students. The challenge for a lecturer is how to settle in at the right balance of

power vs. simplicity, or at the right balance of difficulty vs. ease.

offers

a

more

conventional

approach

to

programming

than

does

Classic

ASP.

It

possesses

all

the

features

of

a

modern

programming

language.

The

Classic

ASP

programming

style favors developers coming from HTML coding background, whereas is more suited

to

professional

software

developers.

Given

our

entire

WAD

students

have

taken

C/Delphi

programming

courses,

and

our

aim

is

to

output

software

professionals,

is

a

better

teaching tool for us. enhances the programming concepts the students learned from the

previous courses and provides a good bridge to Advanced Distributed Computing and Advanced

Object- Oriented Programming.

4. THE PROCESS

Our first step was to learn . After reading books and online tutorials, the next step is

practical. We set an implementation server on the laptop in a stand-alone environment. The .NET

Framework requires IIS 5 and the above; Windows 2000 or Windows XP professional will work

with .NET. However, Windows XP home edition or Win

dows 98 won’t work. On the client side,

we can either use or WebMatrix. Among these, only costs money. The .NET

Framework is included inside the package. We also can download the .NET Framework

from the Internet. After the .NET Framework is installed, the

QuickStart Tutorial is set up. It is also found on the Internet. This tutorial is a good

starting point for experienced developers. It is claimed that the readers “should be fluent in HTML

and

general

Web

development

terminolog

y.

……

should

be

familiar

with

the

concepts

behind

interactive Web pages, including forms, scripts, and data access.” More complicated examples can

be found from Microsoft .NET Framework SDK Documentation or Microsoft Visual Studio .NET

Documentation.

The second step was to test the teaching environment. A teaching server was set up for the

Intranet

on

campus.

It

is

configured

for

the

client

computers

in

the

teaching

lab.

is

installed on the client computers. provides two ways to access the Web server: FrontPage

server extensions and File share. The FrontPage server extension is used on our teaching server.

Programming testing has been done on all the major aspects of W

AD. Except a few special ones,

most

of

the

problems

occurred

during

the

testing

were

minor

problems

which,

after

the

communication with our Web technician, were resolved.

Teaching materials have been updated. The major changes have been made on the data interaction,

form and controls, application/session management, and error handling. Given that has

made XML very practical and the using of Web service much easier. A lecture on XML and Web

service

has

been

added. As a

result,

ColdFusion

lectures

are

reduced.

The

assessment

has been

adjusted accordingly.

5. THE PROBLEMS

We

have

to

admit

that

with

is

a

much

more

complicated

client

server

environment

than

the

Classic

ASP

environment.

This

complexity

comes

from

the

configuration system and the integration between the client computers and the Web server.

On server, each level of the application directory can have a configuration file. All

these

configuration

files

are

optional

except

.

A

developer

has

full

control

over

those optional configuration files. Developers become more involved with the server settings via

these files. One problem that happened to several students and myself on our home servers is the

permission

problem.

We

found

our

applications

didn’t

have

permission

to

write

to