Tài liệu J2EE and EJB ppt

07:00 PM
07:00 PM
5/23
J2EE component

a self-contained functional software unit that is
assembled into a J2EE application.

The J2EE specication denes the following J2EE
components:

Application clients and applets

Java Servlet and JavaServer Pages
(JSP)

Enterprise JavaBeans (EJB) components
(enterprise beans) are business
components that run on the server
07:00 PM
07:00 PM
6/23
J2EE Containers

J2EE server provides underlying services in
the form of a container for every component
type

JNDI lookup services

Security

Transaction Management

Remote connectivity

Life cycle management

Deployment services
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07:00 PM
7/23
J2EE Platform Roles

J2EE Product Provider

Tool Provider

Application Component Provider

Application Assembler

Application Deployer

Administrator
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07:00 PM
8/23
J2EE Technologies
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07:00 PM
9/23
J2EE Platform Benefits

Simplified architecture and development

Freedom of choice in servers, tools, and components

Integration with existing information systems

Scalability

Flexible security model
07:00 PM
07:00 PM
10/23
The whole picture
07:00 PM
07:00 PM
11/23
Overview on EJB

Enterprise JavaBean

equivalent to COM+ from .NET

a distributed component model

Based on RMI-IIOP protocol

link between presentation
components hosted by the Web tier
and business-critical data in the
enterprise information system tier
07:00 PM
07:00 PM
12/23
Overview on EJB

Three kinds of enterprise beans:

session beans

entity beans

message-driven beans.

Session beans are intended to be
private resources used only by the
client that creates them
07:00 PM
07:00 PM
13/23
Overview on EJB

Entity beans

represent an object-oriented view of some
entities that are stored in persistent storage,
such as a database

Message-driven beans

process asynchronous messages delivered via
the Java Message Service (JMS) API

Enterprise beans live inside EJB containers,
which provide life cycle management,
transactions, security, persistence, and a variety
of other services for them
07:00 PM
07:00 PM
14/23
JavaBeans vs EJBs

Java Beans

Client-side component
model

Beans tell you what
they can do

Beans have no run time
dependencies

Beans are usually local

Well suited to
developing GUI
applications

Enterprise Beans

Server-side component
model

Implement required
interfaces and methods

Execute within a
container

Usually remote

Well suited to
developing enterprise
scale applications

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