ILP J2EE Stream J2EE 01 Introduction V0.3

8/14/2019 ILP J2EE Stream J2EE 01 Introduction V0.3

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J2EE Overview

Version 1.0.


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September 3, 2009TCS Internal

Course Objective

The Objective of J2EE course are:

To understand multi-tiered enterpriseapplications.

To understand J2EE framework fordeveloping enterprise applications.

To understand various components ofJ2EE like JSP, Servlets, EJB etc. andeffectively use them.

To understand Application Server and itsconfigurations.

To learn and deploy web basedapplications in application server.

To learn supporting technologies like


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What is WWW

The WWW incorporates all of the Internet

services above and much more.You can retrieve documents, view images,animation, and video, listen to sound files,

speak and hear voice, and view programsthat run on practically any software in theworld, provided your computer has thehardware and software to do these things.


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How does WWW work


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HTTP Communication


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HTTP CommandsGET - retrieves the resource identified by

the request URL.HEAD - returns the headers identified bythe request URL.

POST - sends data of unlimited length to

the Web server.

PUT - stores a resource under the requestURL.

DELETE - removes the resource identifiedby the request URL.

OPTIONS - returns the HTTP methods theserver supports.

TRACE - returns the header fields sent withthe TRACE request.


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HTTP Request

An HTTP request is sent by the browser toserver. It will have the command, therequested object, protocol, and anyadditional attribute passed along with the

object.

Command

Protocol/

Version

Component/

Object

Eg: GET /reports/sales/index.html HTTP/1.0


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HTTP ResponseAn HTTP message sent by a server to aclient is called an HTTP response. The initialline of an HTTP response is called the statusline.

It has three parts, separated by spaces: the

HTTP version, a response status code thattells the result of the request, and anEnglish phrase describing the status code.HTTP/1.0 200 OK

Date: Tue, 01 Dec 2001 23:59:59 GMT

Content-Type: text/html

Content-Length: 52

Hello, John!


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J2EE

Java 2 Platform, Enterprise Edition (J2EE)

defines the standard for developingcomponent-based multi-tier distributedenterprise applications.

AJ2EE componentis a self-containedfunctional software unit that is assembledinto a J2EE application along with relatedcomponents.

An enterprise-level platform for developingportable, secure, scalable, distributed, multi-tier business applications.


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J2EE (contd.)

Application logic is divided into components

according to functionThe various application components thatmake up a J2EE application are installed ondifferent machines depending on the tier inthe multitiered J2EE environment to whichthe application component belongs


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J2EE Multi-tier Framework

EJB Container

JSP/ServletContainer

WEB CLIENT

Database/Legacy Systems

ANY CLIENTClient

Tier

EIS Tier

Web

Tier

Business

Tier

Client

Machine

J2EE

Server

DatabaseServer /

Legacy

Server


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J2EE ArchitectureCLIENTSCLIENTS

TIERTIER

External Clientsfrom INTERNET

(Browsers , WAPetc.) Applets

Internal Clientsfrom INTRANET

(Browsers , Desktop

Applications etc.)

Applets,Javabeans

BACK ENDBACK END

TIERTIER

J2EE WEB APPLICATION SERVER TIERJ2EE WEB APPLICATION SERVER TIER

PRESENTATIONPRESENTATIONLOGICLOGIC

(Web Components)

BUSINESS LOGICBUSINESS LOGIC(EJB Container )

ENTERPRISE SERVICES

HTML

JDBC

XML

SERVLETS

JSP

WML

EJB EJB

EJB EJB

EJBEJB

JNDI JMS JTS

RMI - IIOP

Enterprise

Information

Systems

(Databases,

ERP,

Legacy

Systems)


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J2EE offerings for Developer

Java Server Pages

JavaMail API

Enterprise Java

Beans

Java Authentication &

Authorization Service

Java Naming &

Directory Interface

JAXP JAXB JAXR JAXRPC

Java Servlet

Technology

JDBC Java Message Service

J2EE

Java Transaction API

& Service

JTA + JTSSAAJ (Web Services)


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J2EE Application Components

J2EE applications comprises variouscomponents.Client Components

Built using applets which runs onclient machine

Web CompoentsBuilt using Java Servlet technology

and JSP technology which runs onserver.

Business CompnentsBuilt using EJB technolgy which

runs on server.


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Web Components

J2EE Web components can be either servlets

or JSP pagesServlets are Java programming languageclasses that dynamically process requestsand construct responses.

JSP pages are text-based documents thatexecute as servlets but allow a more naturalapproach to creating static content


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Web Components (cont..)

Static HTML pages and applets are bundled

with Web components during applicationassembly, but are not considered Webcomponents by the J2EE specification.

Server-side utility classes can also bebundled with Web components and, likeHTML pages, are not considered Webcomponents.


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Web Tier


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Business Components

Business code, which is logic that solves or

meets the needs of a particular businessdomain such as banking, retail, or finance, ishandled by enterprise beans running in thebusiness tier.


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Business Tier


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EIS TierThe enterprise information system tier

handles enterprise information systemsoftware and includes enterpriseinfrastructure systems such as enterpriseresource planning (ERP), mainframe

transaction processing, database systems,and other legacy information systems.

Related APIs

JCA , JDBC , JMS , Web Services etc


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J2EE Containers

What is a ContainerContainers are the interface between a

component and the low-level platformspecific functionality that supports the

component.How does it work

Container settings are specified for eachcomponent during assembly process before

deployment.What do I get

Support for security, transactionmanagement, JNDI lookup, Remote

connectivity.


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J2EE Containers (cont..)

Manage life cycle ofobjects

Manage transactions

Provide securityResource

optimization

DB pooling

Compiled JSPCaching

Persistence support

CMP (EJB-QL)


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J2EE Roles & Responsibilities

J2EE Product ProviderBuilds Compliant products

IBM Websphere

JBossApplication Component Provider

Develops the application jsp, servlet, ejb

etc.Application Assembler

Resolves dependencies, Deliver deployableapp.

J2EE R l & R ibiliti


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J2EE Roles & Responsibilities(cont..)

DeployerConfigures resources

DB, Roles, Users, etc.

System Administrator / Production SupportRuntime monitoring, Network

administration, Support

Tool Provider

Provides helper tools for managing,deploying, developing, packaging.


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Reference

Stephanie Bodoff, et. al., The J2EE Tutorial,

Sun Microsystems.James Mc Govern, et. al., J2EE 1.4. Bible.

Documents

ILP J2EE Stream J2EE 01 Introduction V0.3