| Case Study ! |
1) I assume that for this Discusssion that u have already downloaded Tomcat3.2.1.zip file from my Download Location and ur Java
JDK1.2.1 and above is well running and so is ur Tomcat.
2) Many programmers have confused the concept of Java Beans with its complexity and every other nutcase
programmer seem to explain Java Bean by that Juggler Bean or that Hi-Fi Business Logic ??? .
3) Let me put in a Simple Language that Simple Guys like u can me can understand
4) Java Beans are primarly used to call some .Java file contents from .JSP file
| JAVA BEAN FILE |
JSP FILE |
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Mr Tom Hanks is the Owner of Tom Hanks Inc.. He decides to give his employees
15 % Raise in Salary for Developers and Others Getting 10% raise in the Salaries , Tom Hanks how ever has the right to
change this percentage more or less and NO ONE ELSE CAN CHANGE THIS BEAN.
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Mr Smith is a new programmer who joined recently his purpose is to write a small JSP program
which calls this BEAN and does some calcutating Work However he cant change the Bean itself but still he can modify look
and feel of JSP code without doing any COMPILING HIMSELF
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Tom Writes Java Bean (.Java File) which he compiles it into class file (.Class File )
and Copies the .Java File into a floppy and deletes the java file from System and Goes Home .
So that Mr. Smith can use this java bean
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Mr Smith is supposed to use this Java Bean into his .jsp file , Smith Can read the bean through his JSP file
But Smith Cant Change Contents
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Directory : Create Directory "BeanDir" under D:\tomcat\webapps\examples\WEB-INF\classes\
and place this file mysimplebean.java in this directory
(That is : D:\tomcat\webapps\examples\WEB-INF\classes\BeanDir\mysimplebean.java)
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Directory : Create Directory "jspdir" under D:\tomcat\webapps\examples\jsp\
and place this file callbean.jsp in this directory
(That is : D:\tomcat\webapps\examples\jsp\callbean.jsp)
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Comilation : Java Bean is to be Compiled by using javac so
D:\tomcat\webapps\examples\WEB-INF\classes\BeanDir\>javac mysimplebean.java
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Comilation : JSP Files need not be Compiled Infact JSP Engine like Tomcat Compiles it for you
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| START TOMCAT |
CALL JSP FILE |
D:\>cd tomcat
D:\tomcat\>cd bin
D:\tomcat\bin>startup
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http://localhost:8080/examples/jsp/jspdir/callbean.jsp
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| Java Bean Code mysimplebean.java ! |
package BeanDir;
import java.util.*;
//This file must be compiled Manually using javac
//cd D:\tomcat\webapps\examples\WEB-INF\classes\BeanDir\mysimplebean.java
public class mysimplebean
{
public String getceoname()
{
String ceonameval = "Tom Hanks CEO of Tom Hanks INC";
return ceonameval;
}
public String ceoemail()
{
String ceoemailval = "[email protected]";
return ceoemailval;
}
public double findtakehome(int salary,String designation)
{
double takehomeamt;
if(designation=="Developer")
{
takehomeamt = salary+(salary*0.15); //15 % Raise in Salary
}
else
{
takehomeamt = salary+(salary*0.10); //10 % Raise in Salary
}
return takehomeamt;
}
}
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| .JSP File callbean.jsp ! Copy and Paste |
<%@ page import = "BeanDir.mysimplebean" %>
<jsp:useBean
id="mybeanid"
class="BeanDir.mysimplebean"
scope="session"/>
<jsp:setProperty
name="mybeanid"
property="*"/>
<html>
<head><title>JSP - Java Bean Demo : James Smith : </title></head>
<body bgcolor="white">
<font size=2 face=verdana>
<center><strong>Simple JSP with JAVA Beans Demo Application Form</strong> <br>
<%
//Auto Compiled by JSP Engine dont use Javac
//No Parameters Passed into Bean
//cd E:/tomcat/webapps/examples/jsp/jspdir/callbean.jsp
String ceoname_ret;
ceoname_ret=mybeanid.getceoname();
out.println("<br>CEO Name : "+ceoname_ret);
//No Parameters Passed into Bean
String ceoemail_ret;
ceoemail_ret=mybeanid.ceoemail();
out.println("<br>CEO Email : "+ceoemail_ret);
out.println("<br><br>");
out.println("<table border=1 bordercolor='maroon' cellspacing=4 cellpadding=4 align=center>");
out.println("<tr align=center valign=middle>");
out.println("<td bgcolor=maroon><font face='verdana' size=2 color=white> ");
out.println("Calling BEAN From JSP </font></td>");
out.println("<td bgcolor=maroon><font face='verdana' size=2 color=white> ");
out.println("BEAN Responding BACK </font></td></tr>");
double takehomeamt_ret;
double totalcost=0;
takehomeamt_ret = mybeanid.findtakehome(5000,"Developer") ;
totalcost=totalcost+takehomeamt_ret;
out.println("<tr align=center valign=middle><td><font face='verdana' size=2>");
out.println("Take Home : James Smith </font></td>");
out.println("<td><font face='verdana' size=2>"+takehomeamt_ret+"</font></td></tr>");
takehomeamt_ret = mybeanid.findtakehome(5000,"Designer") ;
totalcost=totalcost+takehomeamt_ret;
out.println("<tr align=center valign=middle><td><font face='verdana' size=2>");
out.println("Take Home : Andrew </font></td>");
out.println("<td> <font face='verdana' size=2>"+takehomeamt_ret+"</font></td></tr>");
takehomeamt_ret = mybeanid.findtakehome(7000,"Developer") ;
totalcost=totalcost+takehomeamt_ret;
out.println("<tr align=center valign=middle><td><font face='verdana' size=2>");
out.println("Take Home : Peter O Neal </font></td>");
out.println("<td> <font face='verdana' size=2>"+takehomeamt_ret+"</font></td></tr>");
out.println("<tr align=center valign=middle><td>");
out.println("<font face='verdana' size=2><strong>TOTAL COST FOR COMPANY </strong> </font></td>");
out.println("<td> <font face='verdana' size=2>"+totalcost+"</font></td></tr>");
out.println("</table>");
%> </center>
</font>
</body>
</html>
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Final Program Output |
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My Dream to be your Friend and Create a Group of Intelligent and Understanding Programmers
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 If you like this article and/or code mailme or Join our small Java User Group which is by the Programmers for the Programmers ,
Till we meet next time BYE  Kind Regards - James Smith
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Java, J2EE, J2SE and all Java-based marks are trademarks or registered trademarks of Sun Microsystems, Inc.
in the United States and other countries. 
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