Web Component Development with Servlet and JSP Technologies Unit 01
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This document provides an overview of web applications and Java EE 6, describing key technologies such as servlets, JSP, and MVC architecture. It explains how web applications work, the advantages and disadvantages of various execution methods, and the importance of separation of business and presentation logic. Additionally, it discusses job roles within Java EE architecture and the modular design's impact on application migration.
![Java™ EE 6
Java EE is the industry standard for developing portable,
robust, scalable and secure server-side Java applications.
Java EE is built on the solid foundation of Java Platform,
Standard Edition (Java SE).
Java EE is a set of coordinated technologies which includes
the following web application technologies:
Java Servlet 2.6 (Java Specification Requests [JSR] 164)
JavaServer Pages 2.1 (JSR 246)
JavaServer Pages Standard Tag Library (JSR 62)
JavaServer Faces 1.2 (JSR 262)](https://image.slidesharecdn.com/webcomponentdevelopmentwithservletandjsptechnologiesunit01-150729061916-lva1-app6892/85/Web-Component-Development-with-Servlet-and-JSP-Technologies-Unit-01-3-320.jpg)
Web Component Development with Servlet and JSP Technologies Unit 01
- 1. In this session, you will learn to: Describe web applications Describe Java Platform, Enterprise Edition 6 (Java EE 6) Describe web application program execution methods and the advantages and disadvantages of each Describe Java servlet technology Describe JavaServer Pages technology Define three-tier architecture Define Model-View-Controller (MVC) architecture Objectives
- 2. HTML over HTTP Common Gateway Interface (CGI) Servlets JavaServer Pages (JSP) technology JSP Standard Tag Library (JSTL) XML Struts JavaServer Faces Web Application Technologies
- 3. Java™ EE 6 Java EE is the industry standard for developing portable, robust, scalable and secure server-side Java applications. Java EE is built on the solid foundation of Java Platform, Standard Edition (Java SE). Java EE is a set of coordinated technologies which includes the following web application technologies: Java Servlet 2.6 (Java Specification Requests [JSR] 164) JavaServer Pages 2.1 (JSR 246) JavaServer Pages Standard Tag Library (JSR 62) JavaServer Faces 1.2 (JSR 262)
- 4. Java™ EE 6 (Contd.) For a complete list of Java technologies, go to: http://java.sun.com/javaee/technologies/ http://java.sun.com/javase/technologies/
- 5. Java EE 6 SDK
- 6. Web Sites and Web Applications A web site is a collection of static files, HTML pages, graphics, and various other files. A web application is a web site with dynamic functionality on the server. A web application run programs on the server, for example: A browser makes a request, to the server, for an HTML form. The server responds by sending the HTML form back to the browser in an HTTP request stream. Next, the browser sends another request, with data from the HTML form, to the server. The server passes the request and data to a program that responds by sending data back to the browser.
- 7. Execution of CGI Programs A CGI program handling a single request:
- 8. Execution of CGI Programs (Contd.) A CGI program handling multiple requests:
- 9. Execution of Java Servlets A servlet program handling a single request:
- 10. Execution of Java Servlets (Contd.) A servlet program handling multiple requests:
- 11. Advantages of running programs in separate processes over threads: Programs can be written in a variety of languages Web designers can easily reference programs that run in separate processes. Advantages of running servlet programs in threads compared with other languages not in threads: The CPU requirements are lower. Java technologies separate processing code (business logic) from the HTML (presentation logic). The Java language is robust and object-oriented. The Java language is platform-independent. Using Separate Processes or Using Threads
- 12. Java Servlets A servlet is a Java technology component that executes on the server. Servlet programs perform the following: Process HTTP requests Generate dynamic HTTP responses A web container is a special Java Virtual Machine (JVM™) tool interface that manages the servlets and a thread pool.
- 13. JavaServer Pages™ Technology JSP pages are translated into Java servlet classes that are compiled and execute as servlets in the web container. JSP pages should focus on the presentation logic, not on the business logic. This makes for a good design. In JSP pages, custom tags and JSP Expression Language provide for reusable code and separation of concerns. Java code can be embedded into JSP pages. In a Java technology web application, JSP pages are often used in conjunction with servlets and business objects in a Model-View-Controller pattern.
- 14. Demo: JavaServer Pages™ Technology Demo: JavaServerPages Technology
- 15. Concerns When Using Servlets and JSP™ Technology Advantages of JSP technology: Provides high performance and scalability because threads are used Is built on Java technology, so it is platform-independent. Can take advantage of the object-oriented language and its APIs
- 16. Concerns When Using Servlets and JSP™ Technology (Contd.) Disadvantages of JSP technology: If JSP pages are used in isolation, then the scripting code that performs business and control logic can become cumbersome in the JSP pages. JSP pages are also difficult to debug. There is separation of concerns into business logic and presentation logic. There are concurrency issues.
- 17. Web Application – Three-Tier Architecture
- 18. Model-View-Controller (MVC) Architecture in a Web Application
- 19. Model 2 Architecture Deployment diagram of a web container using Model 2 architecture:
- 20. Frameworks are partial implementations on which you can build your components. There are several Model 2 frameworks available: Struts from the Jakarta group JavaServer Faces technology from Sun Velocity from Apache Model 2 Frameworks
- 21. Modular design allows for easier modification of the business logic. Enterprise components can use container-provided services such as presentation, security, transaction, persistence, and life cycle management. Java EE Containers
- 22. Java EE Architecture Example
- 23. Job Roles The modularity of Java EE architecture clearly distinguishes several job roles: Web Designer – Creates View elements Web Component Developer – Creates Controller elements Business Component Developer – Creates Model elements Data Access Developer – Creates database access elements
- 24. A matrix showing the relationship between an architecture’s complexity and robustness, based on the technologies used: Web Application Migration
- 25. In this session, you learned: CGI provided hooks for web servers to execute application programs. Java servlets are similar to CGI, but they execute in a JVM using threading. JSP pages are similar to servlets, but they are better suited for generating HTML content. The Model 2 architecture uses servlets in conjunction with JSP pages to build web applications. Well designed web applications using Model 2 can be easily migrated to more complex Java EE architectures. Summary
Editor's Notes
- #2: Start the session by explaining the objectives listed in Slide 1.
- #3: In this slide, tell the students about the Web application technologies. Start by describing the HTTP. Tell that the HTTP is a request/response protocol between clients and servers. Tell the students that the Servlets, JSP, and Struts will be covered in the later part of this module.
- #4: In this slide, explain to the students about the Java Platform, Enterprise Edition 6 as given in SG.
- #5: Open the hyperlink given in this slide to show to the students the complete list of Java technologies.
- #6: Use this slide to explain to the students about the Java EE 6 SDK.
- #7: Use this slide to explain to the students about the Web sites and Web applications.
- #8: Use Slides 7 and 8 to explain the execution of the CGI programs. Explain about the CGI programs and their advantages and disadvantages, as given in pages 1-9 to 1-12 of the SG.
- #10: Use Slides 9 and 10 to explain the execution of the Java Servlets.
- #12: Use this slide to explain about the advantages and disadvantages of using Servlets over the CGI programs.
- #13: In this slide, explain to the students about the Java Servlets. Tell the students that the Servlets allow you to add dynamic content to a Web server using the Java platform.
- #14: Use this slide to explain about the JavaServerPages technology.
- #15: Use this slide to demonstrate the comparison of JSP and servlet coding to the students. You can run the project, SquaresServlet stored at Datafiles For Faculty\Session01\Demo1\SquaresServlet.zip file in the TIRM CD. This project contains a JSP file, index.jsp, which displays the squares of numbers 0 through 9 in an HTML table. You can show the students the equivalent servlet, SquaresServlet.java, which can be found at Datafiles For Faculty\Session01\Demo1 in the TIRM CD.
- #16: Use Slides 14 and 16 to explain to the students about the advantages and disadvantages of JSP technology. Also, tell the students about when to use Servlets and JSP technology in the Web application.
- #18: Use this slide to explain to the students about the three-tier architecture for Web applications.
- #19: Use this slide to explain about the Model-View-Controller (MVC) architecture in Web application.
- #20: Use this slide to explain about the Model 2 architecture. In the Model 2 architecture, Servlets control the flow of the web application and delegate the business logic to external components, such as JavaBeans or EJBs, while JSP pages generate the HTML for web browsers.
- #21: Use this slide to explain about the Model 2 frameworks.
- #22: Use this slide to explain about the Java EE containers. Explain that the containers are the interface between a component and the low-level platform-specific functionality that supports the component. Before the execution of a web application, it must be assembled into a Java EE module and deployed into its container.
- #23: In this slide, explain to the students about the Java EE architecture. Also, discuss about its features such as scalability, extensibility, and maintainability.
- #24: Use this slide to discuss about the Job roles.
- #25: Use this slide to explain a matrix of the relationship between an architecture’s complexity and robustness, based on technologies used.
- #26: End the session by discussing the summary points as given in Slide 26.