1、1,Introduction to Java 2 Enterprise EditionPresented by Communication & Collaboration Technologies Division of the Chief Information Officer Rensselaer Polytechnic Institute,Welcome!,2,Main Topics,Introduction The Goal The Problem The Solution What is J2EE? The J2EE FrameworkCase Studies / Examples,
2、3,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.,4,Introduction,IT must provide: High quality services Highly Available Secure ScalablePowerful services
3、 Useful Flexible Extensible Affordable,5,The Problem,produce purchase support maintain replace,Complex software is expensive to:,Difficult Tasks!,6,?,The Problem,Why not delegate components to different departments? Departmental solutions are: Limited in scope Difficult to be aware of enterprise- wi
4、de requirements and initiatives Difficult to leverage Diverse interoperabilty standards,7,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
5、existing standards and software components Strength: Leveraged departmental core compentencies Strongly defined roles and software interfaces allow maximum collaboration,The Solution,8,What is J2EE?,What is Java 2 Enterprise Edition?“The Java 2 platform, Enterprise Edition reduces the cost and compl
6、exity 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.,9,What is J2EE?,Enabling technology Standards based application model A common architecture that prov
7、ides key common functionality: Security Session Management Scalability,J2EE Provides:,10,What is J2EE?,Applications architecture Partitioning of application logic Improves maintainability Simplifies software upgrades and management,What does “multi-tier“ mean?,11,What is J2EE?,Enables increased aggr
8、egate functionality Reduces component maintenance cost Separation of workload to improve scalability and reliability Strong separation prevents vendor lock-in,What does “multi-tier“ mean?,12,Some History,Two tier application (“thin client“)Easy to upgrade client Expensive to scale and to add functio
9、nality,13,Some History,Two tier application (“client/server“)Strong scalability Poor upgradability and difficult management,14,Today,Three tier applicationThin clients make easy upgrades Centralized application server management is easier to manage Model allows for horizontal scalability,15,Today,Th
10、ree tier applicationThin clients make easy upgrades Centralized application server management is easier to manage Model allows for horizontal scalability,client,app server,server,16,Today,17,N-tier applicationView application server as a data store Leverage data abstraction,Today,18,N-Tier Applicati
11、on,19,N-Tier Application,20,N-Tier Application,21,N-Tier Application,22,N-Tier Application,23,N-Tier Complexity,24,Business Logic,25,Business Logic,data,P R O C E S S,O U T P U T,I N P U T,data,26,N-Tier Complexity,27,N-Tier Complexity,28,N-Tier Complexity,29,N-Tier Complexity,30,N-Tier Complexity,3
12、1,N-Tier Complexity,32,J2EE,33,J2EE,Servlets JSP/XML/XSLT,Session Beans,Entity Beans,34,Example: The Kiosk,35,Example: The Kiosk,article,category,get article,client view,admin view,36,Clones,http:/j2ee.rpi.edu/helpdesk,http:/j2ee.rpi.edu/kiosk,http:/www.va.rpi.edu,http:/www.eng.rpi.edu/frame_news.html,37,The J2EE Framework,Java Technologies,External Application,
