Problem in delete form

[William Flores]

Hi guys!
I'm with a problem here.
I have a form, and this form has two buttons "UPDATE" and "DELETE". The button "UPDATE" works normally, but the button "DELETE" isn't works.

<table align="center" cellspacing="30">  
                    <tr>  
                        <td>  
                            <form action = "ServletTutoria" method = "post">  
                                <input type = "hidden" name = "cmd" value = "atualizarTutoria" />  
                                <input type = "submit" name = "btnAtualizar" value = "Atualizar"/>  
                            </form>  
                        </td>  
                        <td>            
                            <form action = "ServletTutoria" method = "post">  
                                <input type = "hidden" name = "cmd" value = "excluirTutoria" />  
                                <input type = "submit" name = "btnExcluir" value = "Excluir" />  
                            </form>  
                        </td>  
                    </tr>                   

In my Servlet, I noticed the parameter is comming null.

else if(cmd.equalsIgnoreCase("excluirTutoria"))  
                {  
                    TutoriaDAO dao = new TutoriaDAO();  
                    MotivoTutoriaDAO motivoTutoriaDAO = new MotivoTutoriaDAO();  
                    Integer ca = Integer.parseInt(request.getParameter("cmpCa"));  
                    motivoTutoriaDAO.excluirMotivos(ca);  
                    dao.excluirTutoria(ca);  
                    rd = request.getRequestDispatcher("/excluidoSucesso.jsp");  
                }  

I didn't understand what's happening, because the button update works normally.
Please anyone help me?

[Bear Bibeault]

What have you done to debug this?

Have you determined what's being submitted as part of the request when the form is submitted? Debug tools in the browser can show you the details of the request.

Have you determined if the conditional check is passing or not? And if not, what's it being compared against that causes it to not work as expected?

This is are just the first of the debugging steps you should take.

[William Flores]

Hi Bear!

I debug, so when I click on the button delete it passing to Servlet, but when it arrives on "Integer ca = Integer.parseInt(request.getParameter("cmpCa"))" is throw a exception saying it's null.
Do you understand me?

[Bear Bibeault]

That's important information that you should have included in the first post. In fact, please post the exact stack trace.

[William Flores]

Follow the throw exception

SEVERE: java.lang.NumberFormatException: null
	at java.lang.Integer.parseInt(Integer.java:417)
	at java.lang.Integer.parseInt(Integer.java:499)
	at br.com.sistemaunicid.controller.ServletTutoria.doPost(ServletTutoria.java:109)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:754)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:847)
	at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1523)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:279)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:188)
	at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:641)
	at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:97)
	at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:85)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:185)
	at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:325)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:226)
	at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:165)
	at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:791)
	at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:693)
	at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:954)
	at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:170)
	at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:135)
	at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:102)
	at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:88)
	at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:76)
	at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:53)
	at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:57)
	at com.sun.grizzly.ContextTask.run(ContextTask.java:69)
	at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:330)
	at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:309)
	at java.lang.Thread.run(Thread.java:662)

[Bear Bibeault]

OK, this line:
at br.com.sistemaunicid.controller.ServletTutoria.doPost(ServletTutoria.java:109)
tells you where to look.

What's at that line, and under what conditions can it result in a NumberFormatException?

Once you've figured that out, back-track to find out how this condition could possibly arise.

[William Flores]

So Bear, I did a test. I changed the form between update and delete.
See below.

<table align="center" cellspacing="30">
					<tr>
						<td>			
							<form action = "ServletTutoria" method = "post">
								<input type = "hidden" name = "cmd" value = "excluirTutoria" />
								<input type = "submit" name = "btnExcluir" value = "Excluir" />
							</form>
						</td>
						<td>
							<form action = "ServletTutoria" method = "post">
								<input type = "hidden" name = "cmd" value = "atualizarTutoria" />
								<input type = "submit" name = "btnAtualizar" value = "Atualizar"/>
							</form>
						</td>
						
					</tr>

Now the button delete works normally, however the button update doesn't works.
This is odd!

[Vic Hood]

What do you mean by it doesnt work ? What exactly is the problem?

[Hemant Thard]

HI William,

I don't see any tag with name "cmpCa" on your JSP page. That's why you are getting null for when you try to search for "cmpCa" on request object.

Now the button delete works normally, however the button update doesn't works.

Yes it should wok because it doesn't execute the following condition :

    else if(cmd.equalsIgnoreCase("excluirTutoria"))    
                    {    
                        TutoriaDAO dao = new TutoriaDAO();    
                        MotivoTutoriaDAO motivoTutoriaDAO = new MotivoTutoriaDAO();    
                        Integer ca = Integer.parseInt(request.getParameter("cmpCa"));    
                        motivoTutoriaDAO.excluirMotivos(ca);    
                        dao.excluirTutoria(ca);    
                        rd = request.getRequestDispatcher("/excluidoSucesso.jsp");    
                    }    

Normally what i will do for debugging is to change the form method from post to get in jsp to check the parameter and value that are to my service method. I would suggest the same for you to check for the presence of any parameter with name "cmpCa".

Regards,
Hemant

[William Flores]

Hi Hemant!

I'll try that, change method post to get

[Bear Bibeault]

There is no need to change the method to GET to check the HTTP parameters. All modern browsers have built-in debugging tools that can be used to inspect the network traffic without resorting to changing the code.

[William Flores]

Hi!

I get solve!
Follow the code

<table align="center" cellspacing="30">
			<tr>
				<td>
					<input type = "hidden" name = "cmd" value = "atualizarTutoria" />
					<input type = "submit" name = "btnAtualizar" value = "Atualizar" />
				</td>
				<td>
					<a href = "ServletTutoria?cmd=excluirTutoria&cmpCa=<%=tutoria.getCa()%>"><input type = "button" value = "Excluir"></a>
				</td>
			</tr>
		</table>

Now, the button update and delete are work normally.
Thanks!