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Web Component Certification (OCEJWCD)

Problem with jspInit() overriding

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posted 13 years ago

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I am using NetBeans6.1 with Tomcat 5.5

to make this program

i am overriding jspInit() method

and tries to fetch "email" parameter that is defined in web.xml

But it shows "null" in index.jsp

i m pasting the code....

...................web.xml..........................

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<servlet>
<servlet-name>
MyTestInit
</servlet-name>
<jsp-file>
/index.jsp
</jsp-file>
<init-param>
<param-name>email</param-name>
<param-value>Deepak@java.com</param-value>
</init-param>

</servlet>

</web-app>

..................index.jsp......................................

<%--
Document : index
Created on : Dec 13, 2008, 1:54:27 PM
Author : Administrator
--%>

<%@page import="javax.servlet.http.*,javax.servlet.*,java.io.*" contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body>

<h2>JSP INIT</h2>
<%! String eMail; %>
<%!
public void jspInit()
{

ServletConfig sConfig=getServletConfig();
eMail=sConfig.getInitParameter("email");
System.out.println("Helloooo"+eMail);
}
%>
<%
out.println("Email Id is "+eMail); //Shows
%> //null

</body>
</html>

Please Rectify it...

if somewhere i am wrong

Thank You

Deepak Bahubal

Constant dripping hollows out a stone....

Devasani Naresh

Greenhorn

Posts: 18

posted 13 years ago

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Have you overridden correct method.
is the signature of the jspInit method is correct?
check if it is like the following.

publc void _jspInit()

Deepak Bobal

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posted 13 years ago

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Naresh Thanks for your response

if you see,i have one

to check if it's being called or not

and it shows it is called

i did that also you suggested me

But still i am getting null

Constant dripping hollows out a stone....

agila arvind

Greenhorn

Posts: 7

posted 13 years ago

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Hi
This code will work , if you add a <servlet-mapping> tag in your web.xml as below
<servlet-mapping>
<servlet-name>MyTestInit</servlet-name>
<url-pattern>/index.jsp</url-pattern>
</servlet-mapping>

Deepak Bobal

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posted 13 years ago

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Arvind as per your suggestion i converts web.xml

as

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<servlet>

<servlet-name>MyTestInit</servlet-name>
<jsp-file>/index.jsp</jsp-file>
<init-param>
<param-name>email</param-name>
<param-value>Deepak@java.com</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>MyTestInit</servlet-name>
<url-pattern>/index.jsp</url-pattern>
</servlet-mapping>

</web-app>

But still it's showing email as null.

Constant dripping hollows out a stone....

Kiril Nugmanov

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Posts: 42

posted 13 years ago

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Hi Deepak Bahubal ,

I think error is that variable eMail is out of page scope. Try to add it to servletcontext scope for example.

PS: I'm not sure about correctness.
[ December 15, 2008: Message edited by: Kiril Nugmanov ]

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Deepak Bobal

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posted 13 years ago

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Hi Kiril

i did the same as you suggested

now

.................index.jsp i..................

<%--
Document : index
Created on : Dec 13, 2008, 1:54:27 PM
Author : Administrator
--%>

<%@page import="javax.servlet.http.*,javax.servlet.*,java.io.*" contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body>

<h2>JSP INIT</h2>
<%! String eMail;
ServletContext ctx; %>
<%!
public void jspInit()
{

ServletConfig sConfig=getServletConfig();
eMail=sConfig.getInitParameter("email");
ctx=getServletContext();
ctx.setAttribute("MyMail", eMail);
System.out.println("Helloooo"+eMail);
}
%>
<%
out.println("Email Id is "+ctx.getAttribute("MyMail"));
%>

</body>
</html>

But still it's showing null...

Constant dripping hollows out a stone....

Kiril Nugmanov

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Posts: 42

posted 13 years ago

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There is no such ctx impicit variable in Servlet. To access servet Context use application implicit variable. Note that your variable that are defined in jspInit are not accessable for the page. Only if you use implicit variable you can access them (or javaBeans). Example could be following:

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Bosun Bello

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Posts: 1512

posted 13 years ago

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Verify that you are accesing the JSP by its given name or mapped URL. What URL are you using to accesing it?

Bosun (SCJP, SCWCD).
So much trouble in the world -- Bob Marley

Deepak Bobal

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posted 13 years ago

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Hi Bosun

i have my project with the name"JspInit"

and using following url to access it

http://localhost:8080/JspInit/web/index.jsp

Constant dripping hollows out a stone....

agila arvind

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if you are accessing it with url http://localhost:8080/JspInit/web/index.jsp , then your servlet mapping must be
<servlet-mapping>
<servlet-name>MyTestInit</servlet-name>
<url-pattern>/web/index.jsp</url-pattern>
</servlet-mapping>

did you check this ?

Seetharaman Venkatasamy

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posted 13 years ago

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Originally posted by Deepak Bahubal:

and tries to fetch "email" parameter that is defined in web.xml

then you can fetch it from

-----------------------------------------------------
<%= config.getInitParameter("email") %> right? why you try to override the jspInit ?

------------------------------------------------------------

Seetharaman Venkatasamy

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posted 13 years ago

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more over you need to check url-pattern of web.xml .can you please post your servlet-mapping part /

Deepak Bobal

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I am pasting web.xml and index.jsp

-----------------------web.xml-------------------

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<servlet>

<servlet-name>MyTestInit</servlet-name>
<jsp-file>/web/index.jsp</jsp-file>
<init-param>
<param-name>email</param-name>
<param-value>Deepak@java.com</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>MyTestInit</servlet-name>
<url-pattern>/index.jsp</url-pattern>
</servlet-mapping>

</web-app>

-------------------------------index.jsp----------------------

<%--
Document : index
Created on : Dec 13, 2008, 1:54:27 PM
Author : Administrator
--%>

<%@page import="javax.servlet.http.*,javax.servlet.*,java.io.*" contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>JSP Page</title>
</head>
<body>

<h2>JSP INIT</h2>
<%! String eMail;
ServletContext ctx; %>
<%!
public void jspInit()
{

ServletConfig sConfig=getServletConfig();
eMail=sConfig.getInitParameter("email");
ctx=getServletContext();
ctx.setAttribute("MyMail", eMail);
System.out.println("Helloooo"+eMail);
}
%>
<%
out.println("Email Id is "+application.getAttribute("MyMail"));
%>

</body>
</html>

Constant dripping hollows out a stone....

Ankit Garg

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Posts: 9692

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posted 13 years ago

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Are you getting null in both the console output and the output of the page?? If yes then I would suggest that you modify the value of the parameter. Just remove the @ symbol and then try as it might not be allowed to use special characters inside parameter values. This is just a guess so it may not work...

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Deepak Bobal

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posted 13 years ago

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Ankit

This guess doesn't work too.

Constant dripping hollows out a stone....

Seetharaman Venkatasamy

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posted 13 years ago

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Originally posted by Ankit Garg:
Just remove the @ symbol and then try as it might not be allowed to use special characters inside parameter values.

not a problem Ankit

and deepak , you are using /inex.jsp and /web/index.jsp ?...

Ankit Garg

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does this also produces null??

out.println("Email Id is "+application.getAttribute("MyMail"));

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Deepak Bobal

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Now the web.xml is

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<servlet>

<servlet-name>MyTestInit</servlet-name>
<jsp-file>/web/index.jsp</jsp-file>
<init-param>
<param-name>email</param-name>
<param-value>Deepakjava.com</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>MyTestInit</servlet-name>
<url-pattern>/web/index.jsp</url-pattern>
</servlet-mapping>

</web-app>

but still not getting the result

Constant dripping hollows out a stone....

Deepak Bobal

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Posts: 96

posted 13 years ago

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yes Ankit

it's still giving null.

i wish at least you try once

Constant dripping hollows out a stone....

Ankit Garg

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posted 13 years ago

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OK. Let me give it a shot. Where is your JSP page?? Just do one thing, put the JSP file in the application root folder i.e. just side by side to web-inf folder. Now use this web.xml

Then just call the webapp with it's name. Eg if the context root of the web-app is myApp, then access it using localhost:8080/myApp/ . Now I think it will work...
[ December 16, 2008: Message edited by: Ankit Garg ]

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