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Web Component Certification (OCEJWCD)

Simple Tag with Attribute

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posted 14 years ago

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I am trying to runt the program mentioned in HFSJ .pg.521

Where am i supposed to set the attribute for setMovieList.
Is it by using
<jsp:setProperty >
if yes how. Do i have to set two properties - name and genre?

The servlet code is:

JSP Tag Invocation

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Christophe Verré

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It looks like you need to set an attribute called "movieCollection" in a scope. There are different ways to do it. One would be to make a servlet, set the "movieCollection" attribute in the request scope, and forward to the JSP file. Can you figure out how to do it ?

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Nabila Mohammad

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posted 14 years ago

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From your response , This is what i could come up with ...

But it still doesn't map anyway to the MyTag.jsp
How do I make this work :

And also , how do i link it to SimpleTagAttr.java file...?

If you could give me a little more help , I ll try to figure it out.

Thanks!

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Ankit Garg

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posted 14 years ago

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Your movieCollection contains Strings, the elements in that list should be Objects of type Movie...

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Nabila Mohammad

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posted 14 years ago

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Does that mean creating a Movie class with set and get methods.

And creating Movie objects and setting the name property to the name of the movie..

and then adding them to List...?

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Christophe Verré

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Great Nabila, you were very close

And creating Movie objects and setting the name property to the name of the movie.

Yes, a Movie class with a name and a genre.

Waiting for your next answer.

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Nabila Mohammad

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posted 14 years ago

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This is the file i created (Hope its Correct!) :

Movie.java

MyServlet.java

import javax.servlet.http.*;
import javax.servlet.*;
import java.io.*;
import foo.Movie;

public class MyServlet extends HttpServlet
{

public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException

{

Movie ob1=new Movie();
ob1.setName("The DaVinci Code");
ob1.setGenre("Drama");

Movie ob2=new Movie();
ob2.setName("The Wedding Planner");
ob2.setGenre("Romance");

Movie ob3=new Movie();
ob3.setName("Matrix");
ob3.setGenre("Action");

Movie ob4=new Movie();
ob4.setName("Live Free or Die Hard");
ob4.setGenre("Action");

Movie ob5=new Movie();
ob5.setName("Shawshank Redemption");
ob5.setGenre("Drama");

java.util.ArrayList  movieCollection = new java.util.ArrayList();  
  
  
movieCollection.add(ob1);  
movieCollection.add(ob2);  
movieCollection.add(ob3);  
movieCollection.add(ob4 );  
movieCollection.add(ob5);

request.setAttribute("movieCollection" ,movieCollection);

RequestDispatcher view= request.getRequestDispatcher("MyTag.jsp");
view.forward(request,response);

}

I still have to create the Web.xml file.
But i cant figure out how the Tag handler class ie.SimlpleTagAttr. java is going to be linked to the Servlet...

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Christophe Verré

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I still have to create the Web.xml file.

"web.xml", all you need is too declare your servlet and its url mapping. You should have seen this already in your book.

But i cant figure out how the Tag handler class ie.SimlpleTagAttr. java is going to be linked to the Servlet...

Tag handlers are not linked to servlets. Your servlet just puts a List in the request scope, and forwards the request to your JSP file. Once the JSP is called, the container will see your tag, and will look for its class, using a TLD (Tag Library Descriptors). You have to make a TLD for your tag, and put it under WEB-INF. This should also be explained in your book.

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Salil Vverma

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posted 14 years ago

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You shall have to make the tld file to get the tag working. The sample tld for your code is as mentioned below. You shall have to put this file in web-inf directory.

Regards
Salil Verma

Nabila Mohammad

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What's the url supposed to be...?

http://localhost:8080/SimpleTagAttr/MyTag.jsp

-OR-

http://localhost:8080/SimpleTagAttr/MiSer.do (And why)

My Web.xml file is

And the rest of the files are same.

I am getting this error with both the urls:

org.apache.jasper.JasperException: Exception in JSP: /MyTag.jsp:8

5:
6: THe movie list is :
7: <table>
8: <myTags:simple movieList="${movieCollection}">
9:
10:
11:

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Christophe Verré

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What's the url supposed to be...?

You want to call your servlet, which will redirect to the jsp. So you should use the servket mapping that you defined in web.xml : http://localhost:8080/SimpleTagAttr/MiSer.do

I am getting this error with both the urls:

Your tag is not closed.

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Nabila Mohammad

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I did close my tag with </myTags:simple> before closing the table.

Either way , its not working.. I am getting the same error

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Hasnain Javed Khan

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posted 14 years ago

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Hi Nabila.

Can you post your JSP file as well.

Kind regards.
Hasnain.

UPDATE: Sorry my bad. its already posted.

Kind Regards.
Hasnain.

Ankit Garg

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Can you show the stack trace, what you gave was the output in the browser, check the logs to see what actual exception is coming. Show us the relevant excerpts of the logs. Your getName and getGenre methods are also not public in the Movie class...

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Nabila Mohammad

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posted 14 years ago

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My Jsp file is :

I am also getting this along with the previous error message i mentioned.

root cause

javax.servlet.ServletException: javax.servlet.jsp.JspException: Unable to find a value for "name" in object of class "foo.Movie" using operator "."

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Ankit Garg

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Ankit Garg wrote:Your getName and getGenre methods are also not public in the Movie class...

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Nabila Mohammad

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I am getting the out put:

He movie list is : Now Naming movie and Genre: Now Naming movie and Genre: Now Naming movie and Genre: Now Naming movie and Genre: Now Naming movie and Genre:
The DaVinci Code Drama
The Wedding Planner Romance
Matrix Action
Live Free or Die Hard Action
Shawshank Redemption Drama

I am not getting any value for ${movieCollection}.
Is it because it's an list of objects...

I guess the error was my get method not being public.

Thanks all for taking the time to give me a response on this!

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Hasnain Javed Khan

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Nabila Mohammad wrote:My Jsp file is :

<%@ taglib prefix="myTags" uri="simpleTags" %> <html> <body> THe movie list is : <table> <myTags:simple movieList="${movieCollection}" > Now Naming movie and Genre: <tr> <td>${movie.name}</td> <td>${movie.genre}</td> </tr> </myTags:simple> </table> </body> </html>

I am also getting this along with the previous error message i mentioned.

root cause

javax.servlet.ServletException: javax.servlet.jsp.JspException: Unable to find a value for "name" in object of class "foo.Movie" using operator "."

As Ankit said, the getters in the Movie class are not public.make the getters public. That should solve the problem most probably.

Let us know when you make the changes and try it.

kind Regards.
Hasnain.

Nabila Mohammad

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posted 14 years ago

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Christophe Verré wrote:It looks like you need to set an attribute called "movieCollection" in a scope. There are different ways to do it. One would be to make a servlet, set the "movieCollection" attribute in the request scope, and forward to the JSP file. Can you figure out how to do it ?

i

What are other ways to do it... Just curious!

And why am I not getting any value for ${movieCollection}.

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