J2EE

1
J2EE

• Gina Sousan
• Fall 2007

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What is J2EE?

• Java 2 Enterprise Edition now known simply as
  Java Enterprise Edition
• Developed by Sun Microsystems
• Unveiled in 1999 at the Sun One Conference
• A framework for creating enterprise applications

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What is the scope of J2EE?

• JSPs
• Servlets
• EJB
• JDBC
• JTA, JTS
• JNDI
• JMS
• RMI

• JAXP
• JAF
• JCX
• JAAS
• JMX
• Java Server Faces

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J2EE Tier
Client App Browser
Middle Web EJB
Persistence DB
JDBC/ JTA,JTS
Request
- Web components and EJB containers -
Communication via JMS, RMI, JNDI, XML, etc.
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Middle layer - Web

• Presentation Layer
• Provides dynamic content in response to requests
• Generates interactive web pages with various
  types of markup languages (XML, HTML)
• Servlets, JSPs, Java Server Faces

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Middle Layer - Web

• Service-oriented
• Implements endpoint of a web service
• Normally provides services to presentation-oriente
  d clients
• JAXP, SOAP, JMS

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Web Components - example

• Request received by client
• JSP page requests data from web service
  (servlet)
• Service sends data to JSP page
• JSP page bundles data into dynamic HTML to be
  displayed to client

JSP page
Request
DHTML
Request
Data
Servlet
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Middle layer - EJB

• Encapsulates business logic of the application
• Server-side component
• Used for scalability, data-integrity and to
  support variety of clients
• Session, Message-Driven, Entity

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Persistence Layer

• Provides object/relational mapping
• Manage relational data in Java applications
• Entity class Java object that maps to a
  database table

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Persistence - illustration
Relational Database
Application
EmployeeEntity.java public class
EmployeeEntity private String name
private int age private String address
Create table employee ( name char(50), age
number, address char(50) )
Defines
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Putting it all together

• Demo