Register / Login

Help coderanch get a

new server

by contributing to the fundraiser

vinal sen

Ranch Hand

+ Follow

news 37 Posts 12 Threads

since Dec 13, 2007

Merit badge: grant badges

For More

Cows and Likes

Cows

Total received

In last 30 days

0

Forums and Threads

Recent posts by vinal sen

useBean with only type attribute(please help)

Thank you Janez and Durran!

Last time,when there was a runtime error in the Jsp:useBean I had given "name" attribute instead of "id".
This time I have so many code problems,I will solve everything.

Janez,in case of redirect(),why is the bean person not found in the request scope?Any ideas?

Thanks

15 years ago

Web Component Certification (OCEJWCD)

useBean with only type attribute(please help)

Bear Bibeault,

I tried my code.It fails at runtime.

Are we not setting the attribute "person" in the request scope? then why is it trying to create a new instance?

Could you please explain.

thanks,Vinal

15 years ago

Web Component Certification (OCEJWCD)

useBean with only type attribute(please help)

Bear Bibeault,

1."set Property" will only work if the new instance is created,right?

new instance will never be created

bcos

1.there is already an existing attribute "person
2.even if there were not any,with only "type" attribute,no new instance will be created,right.

thanks,Vinal

15 years ago

Web Component Certification (OCEJWCD)

useBean with only type attribute(please help)

I found this code at headfirst servlets and jsp(page 420 Be the container)

here is the code

followed by comments in the book: fails at request time.the container knows that if you have only a type specified there must be a existing bean attribute of that name and scope.

---

my point is:

1.there is already a bean attribute "person" set at scope "request" in the servlet,right?which means the name property "fred" is not set and the original name "evan" is the answer.

2.if only "type" attribute is specified,there should be an existing bean by that name.what do you mean by existing bean? does the above example not mean there is an existing attribute in the request scope.

thank you very much in advance

Vinal

15 years ago

Web Component Certification (OCEJWCD)

jsp:param with jsp:include

thanks Rob Prime!

15 years ago

Web Component Certification (OCEJWCD)

jsp:param with jsp:include

Hai all, Could someone please help me with the code(from HFSJ) below:

JSP that does the include (contact.jsp)

The included header that uses the new param ("header.jsp")

<em> <strong> ${param.subtitle} </strong> </em>

The above example as given in the book,tries to set the subtitle based on the settings in the header.jsp.But it gets the value from "contact.jsp"

Are we using jsp:param just to set how they appear in the "contact.jsp".Is my understanding correct?

Please explain.

Thank you,Vinal

15 years ago

Web Component Certification (OCEJWCD)

scwcd voucher for sale

I have a voucher which expires on May 13th 2009 with free retake for $200. Valid in USA

If anyone is interested,please email at uareat2002@yahoo.com

thanks
Vinal

15 years ago

Blatant Advertising

Cookies example in HFSJ

I could not properly display the file structure.sorry.

under myapplication,I have

result.jsp
form.html
WEB-INF

under WEB-INF, I have

classes

-------

thank you,Vinal

15 years ago

Cookies example in HFSJ

this is my application file structure

c:\
|_______apachetomcat
|___webapps
|_______myapplication
|___form.html
|___result.jsp
|___WEB-INF
|____web.xml
|____classes
|___com
|___example
|___myclasses

1.from myclasses,if I have to use RequestDispatcher what should be the path?

RequestDispatcher rd=request.getRequestDispatcher("result.jsp");
gives me error.

2.Do I have to map jsp file in web.xml?

Please help.Thanks in advance.

Vinal

15 years ago

Cookies example in HFSJ

hai Sudhir!

Tried that also,did not work.Is there anything wrong with my jsp file.

Thanks
vinal

15 years ago

Cookies example in HFSJ

In that example there is

1. "form.html" in which we enter the user name and click submit
2. "cookietest.java" - servlet which adds a cookie and transfer the control to a jsp which again takes to another servlet named "checkcookie.java".in "checkcookie" we retrieve the cookie.

The problem is in the cookietest,trying to use the request dispatcher.I had saved the "result.jsp" directly under tomcat/webapps

when I use this code

it gives me Null Pointer Exception

or

results in result.jsp not found.

I checked the parameter name,cookie name and the location of the file.I am unable to locate the problem.Please help.

Thank you very much.Vinal

package com.example;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
public class cookietest extends HttpServlet{
public void doGet(HttpServletRequest req,HttpServletResponse res) throws IOException,ServletException
{
res.setContentType("text/html");
String name=req.getParameter("username");
Cookie cookie=new Cookie("username",name);
cookie.setMaxAge(30*60);
res.addCookie(cookie);
RequestDispatcher view=req.getRequestDispatcher("../cookieresult.jsp");
view.forward(req,res);
}
}
----------------------
<html>
<form method="GET" action="logserv.do">
<input type="text" name="username">
<input type="submit" value ="SUBMIT">
</form>
</html>
--------------------------------------------
package com.example;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
public class checkcookie extends HttpServlet
{
public void doGet(HttpServletRequest req,HttpServletResponse res) throws
IOException,ServletException
{
res.setContentType("text/html");
PrintWriter out=res.getWriter();
Kookie[] cookies=req.getKookies();
if (cookies!=null)
{
for (int i=0;i<cookies.length;i++)
{
Cookie cookie=cookies[i];
if (cookie.getName().equals("username"))
{
String usern=cookie.getValue();
out.println("hello" + usern);
break;
}
}
}
}
}
---------------
<html>
<body>
<a href="checkcookie.do"> click here </a>
</body>
</html>

Note: replaced Cookie with Kookie to post this topic

15 years ago

ServletContextListener doubt

Sorry Guys! I found out that I had failed to make a context param-name breed(instead it was ddd) thank you.

Moderators: could you please close the topic.thank you.

15 years ago

ServletContextListener doubt

I have been trying to set attributes,using the context parameter and ServletContextListener interfaces.

When I try to test the program (after setting the attributes),the attribute value is null(It does not throw null pointer exception).I had given the context param name

what could be the reason?could someone please help me?

web.xml
<web-app 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/web-app_2_4.xsd"
version="2.4">
<servlet>
<servlet-name>pp</servlet-name>
<servlet-class> com.example.listenertester</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name> pp </servlet-name>
<url-pattern>/test.do</url-pattern>
</servlet-mapping>
<context-param>
<param-name>ddd</param-name>
<param-value>great dane</param-value>
</context-param>
<listener>
<listener-class> com.example.mylistener</listener-class>
</listener>
</web-app>
---------
package com.example;
import javax.servlet.*;
public class mylistener implements ServletContextListener
{
public void contextInitialized(ServletContextEvent event)
{
ServletContext sc=event.getServletContext();
String dogbreed=sc.getInitParameter("breed");
Dog d=new Dog(dogbreed);
sc.setAttribute("ddd",d);
}
public void contextDestroyed(ServletContextEvent event)
{}
}
-----------
package com.example;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
public class listenertester extends HttpServlet
{
public void doGet(HttpServletRequest req,HttpServletResponse res) throws IOException,ServletException
{
res.setContentType("text/html");
PrintWriter pw=res.getWriter();
pw.println("testing context attributes set by listener <br>");
pw.println("<br>");
Dog dog=(Dog)getServletContext().getAttribute("ddd");
pw.println("dog's breed is" + dog.getBreed());
}
}

[ October 16, 2008: Message edited by: Bear Bibeault ]

15 years ago

new to scjp,find HFSJ hard

to understand...though they have tried their very best with multiple teaching styles.I accept this subject will be boring without conversation style,pictures,etc.But I think some depth is required to make us understand.(eg. I could hardly understand if a big file structure is needed for the first beer application and if I cut down on some of the folders and store all the files in a single folder,nothing would work)

From the time,I started to setup tomcat I have been reading some other resource or internet besides this book.

Has anyone tried Hanumant deshmukh 2nd edition and found it helpful?

15 years ago

Web Component Certification (OCEJWCD)

first program error, something is missing

Hello kuldeep!

I am also in the same stage as yours! Getting introduced to servlets for the first time.I also got errors like yours.

1.I did not change directory structure.I did it exactly as given in the book.
2.we receive the errors because:
a.we fail to copy the files in the deployment structure
b.we fail to correctly set the classpath,environment variables like catalina and java_home variable
c.in the classpath we forget to include servlet-api.jar

It worked perfectly after I corrected these mistakes.

thanks

16 years ago