Java server pages


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java server pages technology introduction, how it works and how to create. java bean technology

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Java server pages

  1. 1. JAVA SERVER PAGES by Tanmoy Barman cont:-
  2. 2. DISCUSSIONS  Introduction  JSP vs. ASP  JSP life cycles  JSP errors  JSP comments  JSP elements; Directives, Scripting, Actions  JSP implicit objects  Example of writing JSP  Java Bean
  3. 3. INTRODUCTION  JSP is a technology based in java which produces dynamic web pages.  JSP is a server side scripting language technology created by sun micro systems.  JSP files are html files which contains special tags where java code is embedded into it.  JSP have .jsp extension.
  4. 4. JSP VS. ASP  JSP is technology introduced by Sun micro systems where as ASP is a technology introduced y Microsoft.  JSP is abbreviation of JAVA SERVER PAGES and ASP is abbreviation of ACTIVE SERVER PAGES  ASP pages can connect to my sql & ms Access databases and also can connect to other database with the help of ADO whereas JSP can connect to any database loading the appropriate driver when needed.
  5. 5. JSP VS. ASP  ASP runs on Microsoft IIS server which run on Microsoft operating system where as JSP can run on any Linux based server, IBM JBOSS as well as in Microsoft platform.  ASP is an interpreted language, JSP can interpreted as well as compiled.  JSP is free of cost including JSP server where as ASP is free but running ASP on Microsoft IIS server cost money.
  6. 6. JSP LIFE CYCLES  JSP are deployed in the web server as servlet.  The JSP page is compiled to servlet by JSP engine, eliminating the html tags and putting them inside out.println() statements and removing the jsp tags.  Once it is translated into servlet then the servlet, then it follows the servlet lifecycles.
  8. 8. JSP ERRORS  Three types of error can be evolved in JSP:-  Jsp error; which occurs when jsp is translated to servlet.  Java code error; occurs when the servlet is complied to java class.  HTML error; occurs during the presentation of html pages in the browser.
  9. 9. JSP ERRORS  The first two errors (jsp error and java code error) is detected by the application server.  The HTML error is detected by the web browser.
  10. 10. JSP COMMENTS  Comments can be include in the jsp page, follows:-  <%-- --%>  </* */>  <!-- --!>
  11. 11. JSP ELEMENTS  The elements in jsp contains the tags, each having special meanings, containing java codes which tells the jsp engine what/how dynamic output has to processed.  There are three types of elements:-  Directives  Scripting  Action
  12. 12. DIRECTIVES  Directives:- This tag is used to convey special information about the page to the jsp engine.  Syntax:-  <%@ %>  Three kinds of Directives are available:-  page  include  tag library
  13. 13. DIRECTIVES  page directive ; this directive informs the jsp engine about the headers and facilities that the page should get from the environment.  There can be any number of page directives in a jsp page.  Declared usually at the top.  Syntax:-  <%@page attribute= %>  Attributes can be; include, import, session, etc.  Example; <%@page import=“package_name”%>
  14. 14. DIRECTIVES  Include directive ; this is used to statically include one or more resources to the jsp page.  This allows the jsp developer to reuse the code.  Syntax:-  <%@include page=“”%>  There is only on attribute named „page‟ in include directive.
  15. 15. SCRIPTING ELEMENTS  Scripting Elements; contains embedded java code.  There are three types:-  Declarations  Expression  Scriplets
  16. 16. SCRIPTING ELEMENTS  Declarations; this tag allows the developer to declare one or multiple variable and methods.  They do not produce any output.  Syntax:-  <%! %>  Example:- <%! public String name; public int age; public void setDetail(name,age); %>
  17. 17. SCRIPTING ELEMENTS  Expression; this tag allows the developer to embed single java expression which is not terminated by a semi colon.  Syntax:-  <%= %>  Example:- <%= new java.util.Date() %>
  18. 18. SCRIPTING ELEMENTS  Scriplets; this tag allows the developer to embedded java code inside it that can use the variable declared earlier.  Syntax:-  <% %>  Example:- <% int sum=a+b; system.out.println(sum); %>
  19. 19. ACTION ELEMENT  Functions provided like:-  Use of java bean technology in jsp page.  Browser independent support for applet.  Transfers control among pages.  Syntax:-  <jsp: />
  20. 20. ACTION ELEMENT  Standard action tag are:-  useBean  setProperty  getProperty  param  include  forward  plugin
  21. 21. JSP IMPLICIT OBJECTS  There are certain objects in jsp that can be used in jsp page without being declared these are Implicit objects. There are nine implicit object in JSP:-  application  page  pageContext  config  session  exception  request  response  out
  22. 22. EXAMPLE OF JSP  A simple jsp program to show date using scriplets;” teddyTest.jsp” <html> <head> </head> <body> <h1>JSP Page to show today Date </h1> <% out.println(new java.util.Date()); %> </body> </html>
  23. 23. EXAMPLE OF JSP  Now we will use the implicit object to get values from a html page.  This is a html page to take user inputs “Impli.html” <html> <body> <form ACTION=“ImpliShow.jsp”> Name=<input type=“text” name=“nm”> <input type=“submit”> </form> </body> </html>
  24. 24. EXAMPLE OF JSP  ImpliShow.jsp <html> <body> <% String nm=request.getParameter("usr"); String ag=request.getParameter("age"); out.println (“name:”+nm+””+age:”+ag); %> </body> </html>
  25. 25. JAVA BEAN  Java bean is a self contained class file in java which typically contains;  No argument constructor.  Is seriliziable.  Have getter and setter methods to get and set values of the properties.  According to java white papers java beans are reusable component in java, and they combine various objects into a single one which can be accessed by multiple user.
  26. 26. JAVA BEAN  Jsp use three action tag for use of java bean technology:-  useBean=used to locate or instantiate a bean class.  setProperty=set the property value or values of a bean class.  getProperty=get the property values of a bean class, first the property values are converted into string and then added to the request stream.
  27. 27. JAVA BEAN  <jsp:useBean id= "instanceName" scope= "page | request | session | application" class= "packageName.className" type= "packageName.className“ beanName=“ packgeName.className | <%= expression >" > </jsp:useBean>
  28. 28. JAVA BEAN  Example of useBean action tag in jsp:-  Class student{ private String name; Private int age; public void setName(string n){ name=n;} publci void setAge(int a){ age=n;} }
  29. 29. JAVA BEAN  A html page named bean.html <html> <body> <form ACTION=“teddyBean.jsp”> Name=<input type=“text” name=“nm”> <input type=“submit”> </form> </body> </html>
  30. 30. JAVA BEAN  A jsp page named teddyBean.jsp <html> <body> <jsp:useBean id=“obj” class=“student”> <% Sting n=request.getParameter(“name”); obj.setName(n); system.out.println(obj.getName()); %> </body> </html>
  31. 31. JAVA BEAN  <jsp:setProperty name="instanceOfBean" property= "*" | property="propertyName" param="parameterName" | property="propertyName" value="{ string | <%= expression %>}" />  <jsp:getProperty name="instanceOfBean" property="propertyName" />
  32. 32. JAVA BEAN  <jsp:setProperty name=“obj" property="name" value="*" />  To set all the values of the property.  <jsp:setProperty name=“obj” property=“_property” value=“_value” />  To set a particular property with a value.
  33. 33. JAVA BEAN  Example of setProperty and getProperty action tag:- Package teddyPack public class jB { private String name; private int age; public void setAge(int age){this.age=age;} public void setName(String name){;} public String getName(){return name;} public int getAge(){ return age;} }
  34. 34. JAVA BEAN  A html page named “setGET.html” <html> <body> <form ACTION=“setGet.jsp”> Name:<input type=“text” name=“name”> Age:<input type=“text” name=“age”> <input type=“submit”> </form> </body></html>
  35. 35. JAVA BEAN  A jsp page named “setGet.jsp” <html> <body> <jsp:useBean id="ted" class="teddyPack.jB" /> <% String n=request.getParameter("name");%> <jsp:setProperty name="ted" property="name" value="*" /> <b>HELLO</b><jsp:getProperty name="ted" property="name"/>; aged <jsp:getProperty name=“ted” property=“age”/> </body> </html>
  36. 36. THANK YOU