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Jsp (java server page)
The document provides an overview of server-side scripting technologies including CGI, Java servlets, and JSP. CGI scripts are executed on the web server with disadvantages of high server load. Servlets are Java programs that provide platform independence, performance, extensibility, and safety. JSPs simplify server-side scripting by allowing Java code to be embedded within HTML pages and are translated to servlets. The life cycle of a servlet including initialization, processing requests, and destruction is also summarized.
Jsp (java server page)
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- 2. History of Server side scripting Java CGI-Perl JSP Servlets
- 3. CGI (common gatewayinterface) 1. Scripts are linked and executed on the web server. 2. CGI includes Perl, C++, Visual Basic and even java. 3. biggest disadvantage to using CGI was that it placed a tremendous load on your Web server as it is executed on the web server
- 4. Java Servlets Platform Independence Performance Extensibility Safety Secure
- 5. Types of servlet •Generic Servlet Class (Inherit) • HttpServlet Class(Inherit) • Servlet interface (Implement)
- 6. HttpServlet Web Request components Web Client JavaBeans HttpServlet Components Response
- 7. Life cycle ofServlet Import java.io.*; Import javax.servlet.*; Import javax.servlet.http.*; Public class TestServlet extends HttpServlet { public void init() // called only once at start {
- 8. /* It canbe used for those elements which always need an initialization like JDBC but it is optional to use */ } Public void service/doGet/doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException , IOException { /* Common method used for initializing JDBC ,server based operations and redirect to pages. */
- 9. Public void destroy()//terminates the servlet { /* rarely used*/ } }
- 10. JSP(Java Server Page) •Addressing jsp page is simpler than servlets. • Servlet goes with two pages hand in hand like for logging login.html (used as an index) login.java (used for request and response). • Only one page enough login.jsp . JSP provides better compatibility with web development tools.
- 11. Difference in code JavaServlets JSP Class …. <html> { …… …. <% out.print(“welcome user”); out.write(“Login page”); out.print(“<body>”); %> ……… </html> }
- 12. What is JSP? Template for a web page that uses java code to generate HTML documents dynamically. JSP runs in a server side component known as JSP container. JSP Container translates them into equivalent java code. JSP is similar to ASP and PHP, but it uses the Java programming language.
- 13. JSP Fundamentals • <% ….. %> Scriptlets • <%! … %> Declarative • <%@...%> Directive • <%= … %> Expressions
- 14. Jsp program • Filename index.jsp <%@ … %> <html> <body> <form name=“f1” action=“Check.jsp”> Name :- <input type=“text” name=“name” /> <input type=“submit” name=“submit” value=“submit”/>
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- 16. • Check.jsp <%@. %> <html> <body> <% String nm=request.getParameter(“name”); %> <table> <tr> <td> <% out.write(nm)%> </td> </tr>
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- 18. MVC Model Database Model Access Presentation DB Data Model Updates User Input View Next View Controller Delegate State actions Actions
Editor's Notes
- #5 Platform IndependenceServlets are written entirely in java so these are platform independent. Servlets can run on any Servlet enabled web server. For example if you develop an web application in windows machine running Java web server, you can easily run the same on apache web server (if Apache Serve is installed) without modification or compilation of code. Platform independency of servlets provide a great advantages over alternatives of servlets.PerformanceDue to interpreted nature of java, programs written in java are slow. But the java servlets runs very fast. These are due to the way servlets run on web server. For any program initialization takes significant amount of time. But in case of servlets initialization takes place first time it receives a request and remains in memory till times out or server shut downs. After servlet is loaded, to handle a new request it simply creates a new thread and runs service method of servlet. In comparison to traditional CGI scripts which creates a new process to serve the request. ExtensibilityJava Servlets are developed in java which is robust, well-designed and object oriented language which can be extended or polymorphed into new objects. So the java servlets take all these advantages and can be extended from existing class to provide the ideal solutions.SafetyJava provides very good safety features like memory management, exception handling etc. Servlets inherits all these features and emerged as a very powerful web server extension.SecureServlets are server side components, so it inherits the security provided by the web server. Servlets are also benefited with Java Security Manager.