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JSP code to complete a task  RSS feed

 
Rebecca Green
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Hi all,

So glad to find this forum...
I am totally new to servlets and JSP and started to learn from the Head First series a few days ago.
But my teacher gave an assignment in JSP which I have no clue how to do.

Can anyone please help me out??

The assignment is this...

A JSP code to create Employee details with the following fields :
1. Name
2. Salary
3.Employee ID

It should also have options to Add and Modify.
And once the form is filled and saved, a page containing the details of all employees including the newly added one must be displayed.

I am supposed to store it in a database and also be able to retrieve it.

I guess some of you might laugh at me as this appears simple... but I'm a total fresher at this stuff... I need your help people!!
 
Sebastian Janisch
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How exactly are you supposed to solve your task ?

The general approach is to have a servlet do the work (your fields go into a java bean) and the JSP only display the results.
 
David Newton
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What do you have so far?
 
Rebecca Green
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Sebastian Janisch wrote:How exactly are you supposed to solve your task ?

The general approach is to have a servlet do the work (your fields go into a java bean) and the JSP only display the results.


Yeah... I also need to have a servlet which does the work...
And I am going through several examples but have not started to write anything...
 
Jeanne Boyarsky
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Rebecca,
As a suggestion to start, try breaking it up into smaller pieces.

Can you:
  • Write a class/method that inserts an Employee into the database when passed those three values as Strings?
  • Can you create a Hello World JSP?
  • Can you create a JSP with a form?
  • Can you create a servlet that reads three parameters?
  • Can you hook together the whole thing?

  •  
    chaitanya karthikk
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    Hi Rebecca, it is simple, I will be explaining you how to do that.

    step 1: code a html page which asks the user to enter his or details.

    step 2: write a servlet which implements the doGet() or doPost() method based on the method you used in the html form. note: if you use post method in your html form and implement doGet() method in the servlet then you will get an error. So be cautious.

    step 3: In the controller get the values sent from the html page. Now you have to create a model which actually stores the data in the database.

    step 4: the controller is responsible for calling the model, the controller passes the values received from the html page to the model. the model saves the data.

    step 5: the model is responsible for connecting to the database.

    step 6: after the model executes successfully, now you have to call a jsp page from the controller to display the data you have stored in the database.

    step 7: save the sevlet class file in WEB-INF classes folder.

    step 8: In the deployment descriptor map the servlet and html page.

    Your project structure must look like this.



    Hope you understood, have a nice day

    If I am wrong anywhere please let me know.
     
    Bear Bibeault
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    anusha chaitanya wrote:If I am wrong anywhere please let me know.

    One problem I see is that all classes involved with a web application should be in a package other than the default.
     
    David Newton
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    And there's a source file deployed.

    (And I'm not convinced the model should be what does the DB access, but that's a different type of issue.)
     
    Bear Bibeault
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    ... and the JSP should be hidden behind WEB-INF to prevent direct access.
     
    chaitanya karthikk
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    Bear Bibeault wrote:... and the JSP should be hidden behind WEB-INF to prevent direct access.


    Thanks Bear for those suggestions, as she is a beginner I proposed her that architecture.
     
    David Newton
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    But it won't run if the servlet is in the default package...
     
    Bear Bibeault
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    anusha chaitanya wrote:Thanks Bear for those suggestions, as she is a beginner I proposed her that architecture.

    Making poor practice suggestions, especially to a beginner, is not a good idea. It instills bad habits that must be unlearned later.
     
    chaitanya karthikk
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    Making poor practice suggestions, especially to a beginner, is not a good idea. It instills bad habits that must be unlearned later.

    Thank you Bear, next time I ll try my level best to help others.
     
    Bear Bibeault
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    anusha chaitanya wrote:I ll try my level best to help others.

    I like your attitude!
     
    chaitanya karthikk
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    Bear Bibeault wrote:
    anusha chaitanya wrote:I ll try my level best to help others.

    I like your attitude!


    Thank you sir.
     
    Rebecca Green
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    I finished the first part of the assignment... the add option... thanks guys
    Your answers helped a lot. But I still need to do a lot of work and add a 2 more options - Modify and Delete. I did that to some extent, but its not working!
    I will paste my code here. please tell me where the error might be...
    I have taken a seperate servletfor deleting called DeleteDb.
    I have placed a 'Delete' button in the jsp page which is used to retrieve the table from the database.

    In the jsp page, I have added checkboxes and have placed a delete button such that upon clicking, it goes to the DeleteDB servlet :



    Here is the DeleteDB servlet code :


    please point out what might have gone wrong. Also, what all changes shoyld I make to this code in order to implement 'Modify' option...

    Thanks
     
    chaitanya karthikk
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    the if else is not placed properly. what is the error you are getting

     
    chaitanya karthikk
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    And one more thing is I think you are selecting multiple checkboxes and clicking the delete button. If I am right, then for that kind of job this logic is not correct. Use this one.
     
    Rebecca Green
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    Its not placed peoperly??
    Can you elaborate it a little more...??

    And the 'else' part is displaying once i click on the 'Delete' button... i mean, "Error while deleting" is being displayed.
     
    chaitanya karthikk
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    Rebecca Green wrote:Its not placed peoperly??
    Can you elaborate it a little more...??

    And the 'else' part is displaying once i click on the 'Delete' button... i mean, "Error while deleting" is being displayed.


    The if-else statement is not placed properly.
    it is not


    It is

     
    chaitanya karthikk
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    Rebecca Green wrote:

    And the 'else' part is displaying once i click on the 'Delete' button... i mean, "Error while deleting" is being displayed.


    since you are dispatching the request to the next page you are unable to see the "Error while deleting" statement
     
    Rebecca Green
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    anusha chaitanya wrote:And one more thing is I think you are selecting multiple checkboxes and clicking the delete button. If I am right, then for that kind of job this logic is not correct. Use this one.


    I tried this... now i'm getting "java.lang.NullPointerException " once i click on the delete button
     
    chaitanya karthikk
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    Can you paste all the pages, or send it to my mail id.
     
    Rebecca Green
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    Sure... will send it right away

    Thanks
     
    Rebecca Green
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    I sent it to the mail id mentioned in your profile... is that correct...??
     
    chaitanya karthikk
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    Rebecca Green wrote:I sent it to the mail id mentioned in your profile... is that correct...??


    yes
     
    Bear Bibeault
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    Rebecca and anusha, please use the forum not email.

    Please read this for more information.
     
    Rebecca Green
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    Problem solved!! Thanks Anusha!!
    The problem was a small one. I had to place the <form> tag inside the while loop and thats it



    This was the change made. If anyone wants teh complete code, feel free to PM me.
     
    It is sorta covered in the JavaRanch Style Guide.
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