Training Program 1 Web Applications

1
Training Program 1Web Applications

• 4/17/2006
• Tokuda Lab
• NAGAI Takashi

2
Contents

• Tutorial 1 World Wide Web
• Tutorial 2 Web Applications
• Exercise 1 Make a Web application

3
World Wide Web

• System to share the resources over the Internet
• Communicate with Client-Server architecture
• Web or WWW for short

Server
The Internet
Client
Resource
4
URI, Resource, Representation

• Resource
• Not only information resource.
• Dog, Mail box, ...
• URI
• Identify the resources.
• HTTP
• To get representation.
• Most popular protocol.
• XML
• Most popular data format

5
Web Applications

• Human interaction system.
• Documents Linked with Hyper Links.
• Not only to view information, but also to make
  side effect.
• Non installed application ? Easy to manage

6
Example
7
Data flow in Web applications
request
GET /hello.jsp?namenagai HTTP/1.1
click link, submit form,
parameter
HTTP
rendering
File or Program
Browser
Web AppServer
HTTP/1.1 200 OK Content-Type
text/html lthtmlgtltheadgt
response
8
Programs in Web applications

• Server-Side Program
• CGI, Java (JavaServlet, JSP), ASP.NET, PHP and
  etc
• Client-Side Program
• HTML, JavaScript, JavaApplet, Flash and etc
• Multi-Layered Server-Side Program
• For reliability and querying

query or data
parameter
data
Web server
Program
Database
9
JavaServlet

• A action of Web application are coded as a
  function of Java class.

Compile
Load
Execute
HelloWorld.java
HelloWorld.class
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Example JavaServlet

• public class HelloWorld extends HttpServlet
• public void doGet(HttpServletRequest request )
• response.setContentType("text/html
  charasetShift_JIS")
• String name request.getParameter("name")
• PrintWriter out response.getWriter()
• out.println("lthtmlgtltbodygt")
• out.println("Hello!")
• out.println(name)
• out.println("lt/bodygtlt/htmlgt")
• public void doPost() doGet(request, response)
  

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Server-Page Style JSP

• Programs are directly embedded in the HTML.
• JSP code is transformed to Java code by the
  container.

Compile
Load
Transform
Execute
hello_jsp.java
hello_jsp.class
hello.jsp
The container processes automatically
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Example JSP

• lt_at_ page contentType"text/html
  charasetShift_JIS" gt
• lt
• String name request.getParameter("name")
• gt
• lthtmlgtltbodygt
• Hello! lt name gt
• lt/bodygtlt/htmlgt

13
Technologies

• Today
• Object-Oriented Framework
• Server-Page Style Coding
• UI Component Visualizing Tool
• Simple Application Generator
• Future
• MDD Model-Driven Development
• Advanced Application Generator
• Rich Client

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Development of Web applications

• Should think
• Architecture design
• Multi-layer, Model-View-Controller,
• Developing tools, Testing, Methodology
• Session management
• Security

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Session management

• HTTP is stateless protocol.
• In the case of screen transition, the mechanism
  holding states is needed.
• Cookie, Hidden field, Session variable,

Server
Client
login.jsp
I am Nagai.
Hello! Nagai.
namenagai
cart.jsp
I ll take a book.
Who are you?
Nagai bought a book.
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Security

• The Web is open and plan-text communication.
• The servers store most of data.
• Various security issues peculiar to Web
  application
• XSS,Parameter manipulation, Forced browsing, SQL
  injection, Session hijacking and etc
• At programming step, some issues can be
  prevented.
• Checking input data, data storing place,

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Exercise 1

• Make a Web application.
• Personal information management system
• ? Example
• The high function and the splendid presentation
  are not required.
• If you have surplus energy, you may do it.
• The KISS Principle Keep It Simple, Stupid!
• I recommend Java or .NET.
• Relate to next programs.
• Deadline Next Monday?

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Exercise 1 contd

• Thinking points
• Reusefullness, Transformability, Learning cost,
  Developing speed, Dependency, Processing
  efficiency, Security and Total balance.
• Group
• Negishi, Moriya
• Ohotake, Minami
• Hai, Tei,
• Sonoda
• Old members support new comers.
• Ask seniors any kind of trifling problem.

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Information source 1/2

• General
• Local Wiki in http//namacha/wiki/index.php/World_
  Wide_WebRefer to this, and cooperate with
  making.
• http//www.w3schools.com/
• World Wide Web
• Architecture of the World Wide Web, Volume One
  . W3C Recommendation 15 December 2004.
  http//www.w3.org/TR/2004/REC-webarch-20041215/.
• Web??????? ?1?. ?? ?? ?. http//www.fxis.co.jp/
  xmlcafe/W3Ctranslation/REC-webarch-20041215-jpn.ht
  ml.

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Information source 2/2

• Web Application
• Ask seniors or Google.
• JavaWorld Magazine
• Web???????????? http//tokuda-www.cs.titech.ac.
  jp/local/webapplidevelopment/, some old.