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Introduction to J2EE
Welcome!
Introduction to
Java 2 Enterprise Edition
Presented by
Communication & Collaboration Technologies
Division of the Chief Information Officer
Rensselaer Polytechnic Institute
1
Introduction to J2EE
Main Topics
• Introduction
– The Goal
– The Problem
– The Solution
• What is J2EE?
• The J2EE
Framework
• Case Studies /
Examples
2
Introduction to J2EE
Introduction
“Enterprises today need to
extend their reach, reduce
their costs, and lower their
response times”
– Simplified Guide to the Java 2 Platform,
Enterprise Edition, Sun Microsystems, Inc.
3
Introduction to J2EE
Introduction
IT must provide:
• High quality services
– Highly Available
– Secure
– Scalable
• Powerful services
– Useful
– Flexible
– Extensible
• Affordable
4
Introduction to J2EE
The Problem
Difficult Tasks!
Complex software is expensive to:
•
•
•
•
•
produce
purchase
support
maintain
replace
5
Introduction to J2EE
The Problem
Why not delegate components to
different departments?
Departmental solutions are:
• Limited in scope
– Difficult to be aware of enterprisewide requirements and initiatives
• Difficult to leverage
– Diverse interoperabilty standards
6
Introduction to J2EE
The Solution
• Cost and complexity
– Solution: Leverage reusable software components
• Limited scope and impact
– Solution: Provide interfaces that enable enterprise-wide
application development
• Diverse standards
– Solution: Utilize existing standards and software components
• Strength: Leveraged departmental core compentencies
– Strongly defined roles and software interfaces
allow maximum collaboration
7
Introduction to J2EE
What is J2EE?
What is Java 2 Enterprise Edition?
"The Java 2 platform, Enterprise Edition
reduces the cost and complexity of
developing ... multi-tier services,
resulting in services that can be rapidly
deployed and easily enhanced“
– Simplified Guide to the Java 2 Platform,
Enterprise Edition, Sun Microsystems, Inc.
8
Introduction to J2EE
What is J2EE?
J2EE Provides:
• Enabling technology
• Standards based application model
• A common architecture that provides
key common functionality:
– Security
– Session Management
– Scalability
9
Introduction to J2EE
What is J2EE?
What does "multi-tier" mean?
• Applications architecture
• Partitioning of application logic
• Improves maintainability
• Simplifies software upgrades and
management
10
Introduction to J2EE
What is J2EE?
What does "multi-tier" mean?
• Enables increased aggregate functionality
• Reduces component maintenance cost
• Separation of workload to improve
scalability and reliability
• Strong separation prevents
vendor lock-in
11
Introduction to J2EE
Some History
Two tier application ("thin client")
*
client
server
• Easy to upgrade client
• Expensive to scale and to add functionality
*Business Logic
12
Introduction to J2EE
Some History
Two tier application ("client/server")
client
server
• Strong scalability
• Poor upgradability and difficult management
13
Introduction to J2EE
Today
Three tier application
client
app server
server
• Thin clients make easy upgrades
• Centralized application server management
is easier to manage
• Model allows for horizontal scalability
14
Introduction to J2EE
Today
Three tier application
client
app server
server
• Thin clients make easy upgrades
• Centralized application server management
is easier to manage
• Model allows for horizontal scalability
15
Introduction to J2EE
Today
16
Introduction to J2EE
Today
N-tier application
• View application server as a data store
• Leverage data abstraction
17
Introduction to J2EE
N-Tier Application
18
Introduction to J2EE
N-Tier Application
Banner
LDAP
19
Introduction to J2EE
N-Tier Application
20
Introduction to J2EE
N-Tier Application
21
Introduction to J2EE
N-Tier Application
22
Introduction to J2EE
N-Tier Complexity
23
Introduction to J2EE
Business Logic
24
Introduction to J2EE
data
O
U
T
P
U
T
Business Logic
P
R
O
C
E
S
S
25
I
N
P
U
T
data
Introduction to J2EE
N-Tier Complexity
26
Introduction to J2EE
N-Tier Complexity
27
Introduction to J2EE
N-Tier Complexity
28
Introduction to J2EE
N-Tier Complexity
29
Introduction to J2EE
N-Tier Complexity
30
Introduction to J2EE
N-Tier Complexity
31
Introduction to J2EE
Servlets
JSP/XML/XSLT
J2EE
Session
Beans
32
Entity
Beans
Introduction to J2EE
Servlets
JSP/XML/XSLT
J2EE
Session
Beans
33
Entity
Beans
Introduction to J2EE
Example: The Kiosk
34
Introduction to J2EE
Servlets
JSP/XML/XSLT
Example: The Kiosk
Session
Beans
Entity
Beans
article
client view
get article
restore
category
admin view
utility
35
Introduction to J2EE
Clones
http://j2ee.rpi.edu/helpdesk
http://j2ee.rpi.edu/kiosk
http://www.va.rpi.edu
http://www.eng.rpi.edu/frame_news.html
36
Introduction to J2EE
The J2EE Framework
Java Technologies
External
Application
37