Java Servlets Tutorial | Introduction to Servlets | Java Certification Training | Edureka
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The document provides an overview of Java certification training, focusing on servlets and HTTP communication. It explains the differences between HTTP GET and POST methods, the architecture and life cycle of servlets, and compares CGI with servlets. Additionally, it outlines how to create a simple servlet and details various servlet classes and interfaces.
Java Servlets Tutorial | Introduction to Servlets | Java Certification Training | Edureka
- 1. JAVA CERTIFICATION TRAINING www.edureka.co/java-j2ee-soa-training
- 2. JAVA CERTIFICATION TRAINING www.edureka.co/java-j2ee-soa-training Topics to be covered Introduction to WEB WEB & HTTP HTTP Request & Response What are Servlets? Servlet Classes & Interfaces Servlet Architecture Generic Servlets Servlet Request & Response CGI vs Servlets
- 4. JAVA CERTIFICATION TRAINING www.edureka.co/java-j2ee-soa-training Introduction to Web Request Response is sent to client Client Server Web is basically a system of Internet servers that support specially formatted documents
- 5. WEB & HTTP
- 6. JAVA CERTIFICATION TRAINING www.edureka.co/java-j2ee-soa-training Web & HTTP
- 7. JAVA CERTIFICATION TRAINING www.edureka.co/java-j2ee-soa-training Web & HTTP HTTP is a protocol that clients and servers use on the web to communicate.
- 8. JAVA CERTIFICATION TRAINING www.edureka.co/java-j2ee-soa-training HTTP Request & Response HTTP Request HTTP Response Client Server HTTP Response is the packet of information sent by Server to the Client in response to an earlier Request made by Client HTTP Request is a packet of Information that one computer sends to another computer to communicate something
- 9. JAVA CERTIFICATION TRAINING www.edureka.co/java-j2ee-soa-training Difference between HTTP Get & Post HTTP GET Operation HTTP POST ▪ Data is sent in header ▪ Data is sent in request body ▪ Not secured ▪ It is secured ▪ Can be bookmarked ▪ Cannot be bookmarked ▪ Limited data can be sent ▪ Large amount of data can be sent
- 11. JAVA CERTIFICATION TRAINING www.edureka.co/java-j2ee-soa-training What are Servlets? Creates Web Application Provides Interfaces & Classes Must be implemented to create Servlet Robust & Scalable Deployed to create Web Page Responds to any incoming requests
- 12. JAVA CERTIFICATION TRAINING www.edureka.co/java-j2ee-soa-training What are Servlets? Request Response is generated at runtimeResponse is sent to client Client Server
- 13. CGI VS Servlets
- 14. JAVA CERTIFICATION TRAINING www.edureka.co/java-j2ee-soa-training What is CGI? Common Gateway Interface (CGI) is a standard for writing programs that can interact through a Web server with a client running a Web browser. High Response Time Low Response Time Not Secure Secure Not Scalable Highly Scalable CGI VS SERVLET
- 16. JAVA CERTIFICATION TRAINING www.edureka.co/java-j2ee-soa-training Servlet Architecture Web Browser DatabaseServlet ProgramHTTP Server HTTP Protocol
- 17. JAVA CERTIFICATION TRAINING www.edureka.co/java-j2ee-soa-training Servlet Life Cycle Handling Request Loading & Instantiation Initialized End Start Stop init() service() destroy() End of Request thread
- 18. JAVA CERTIFICATION TRAINING www.edureka.co/java-j2ee-soa-training Steps to create Simple Servlet Create and compile simple servlet code 1 Start Apache Tomcat 3 Add mappings to web.xml file 2 Start Web Browser & Request Servlet 4
- 19. Generic Servlet
- 20. JAVA CERTIFICATION TRAINING www.edureka.co/java-j2ee-soa-training Generic Servlet A generic servlet is a protocol independent Servlet that should always override the service() method to handle the client request.. Generic Servlet is easier to write It has a very simple life cycle methods To write Generic Servlet you just need to extend javax.servlet.GenericServlet and override the service() method Pros
- 21. JAVA CERTIFICATION TRAINING www.edureka.co/java-j2ee-soa-training Request & Response Servlet Request Servlet Response
- 22. JAVA CERTIFICATION TRAINING www.edureka.co/java-j2ee-soa-training Request & Response Servlet Response Servlet Request An object of ServletRequest is used to provide the client request information to a servlet such as content type, content length, parameter names and values, header informations, attributes etc.
- 23. JAVA CERTIFICATION TRAINING www.edureka.co/java-j2ee-soa-training Request & Response Servlet Response Servlet Request An object of ServletResponse is used to write the information back to the client.
- 25. JAVA CERTIFICATION TRAINING www.edureka.co/java-j2ee-soa-training Servlet Classes & Interfaces Servlet Declares life cycle method of servlet ServletConfig Allows servlet to get Initialization methods ServletContext Enables servlet to log access and access information ServletRequest Used to read data from client request ServletResponse Used to write data to client response GenericServlet Implements servlet and Servlet.Config Interface ServletInputStream Provides input stream to read requests from the client ServletOutputStream Provides output stream to write responses to the client ServletException Indicates servlet error has occured UnavailableException Indicates servlet is not available HttpServlet Provides methods to handle Http Request and Response HttpServletRequest Enables servlets to read data from Http Request HttpServletResponse Enables servlets to write data to Http Response