Forum:

Servlets

not getting value in doget method of servlet

Ranch Hand

Posts: 67

posted 16 years ago

Number of slices to send:

Optional 'thank-you' note:

Send

i had to delete rows on basic of checkbox
Procedure which i am doing: --
I had a jsp in which on basic of selection of checkbox i am passing empid value to servlet in which do get method is defined which is calling delete () in another java pagewhich is deleting record

jsp page

<%@page import="java.util.*"%>
<%@page import="java.lang.reflect.Array"%>

<%@page import="mydao.New_USER;"%>
<html>
<head>

<title>Insert title here</title>
</head>
<body> 
  <form Name="Display" Method="get" action="DeleteServlet">

<CENTER> 
    <TABLE CELLSPACING="1" CELLPADDING="4" BORDER="3"> 
        <TR> 
      <TH>Select</TH><TH>EmpID</TH><TH>EmpFName</TH><TH>EmpLName</TH><TH>Department</TH><TH>Designation</TH><TH>Email</TH><TH>Address</TH><TH>Project</TH><TH>Manager</TH>  
        </TR>

ArrayList p = new ArrayList (); 
   ArrayList rows = new ArrayList (p);

if (request.getAttribute("AttributeUser") != null) {
	
   rows = (ArrayList ) request.getAttribute("AttributeUser");  
   
for(int i=0; i< rows.size(); i++) { 
	New_USER user = (New_USER) rows.get(i);
%>
		<tr>
		<td><input type="checkbox" name="Empid" value= <%= user.getEmpid()%> ></td>
		    
			<td>  <%= user.getEmpid()%> </td>
			<td> <%= user.getEmpfname()%>  </td>
			<td> <%= user.getEmplname()%>  </td>
			<td> <%= user.getDepartment()%>  </td>
			<td> <%= user.getDesignation()%>  </td>
			<td> <%= user.getEmail()%>  </td>
			<td> <%= user.getAddress()%>  </td>
			<td> <%= user.getProject()%>  </td>
			<td> <%= user.getManager()%>  </td>
			
		</tr>

<%}}%>

</Table>

<%   
      
       String str=request.getParameter("value"); 
   System.out.println(" Str" + str);  
    ArrayList items=new ArrayList();  
    ArrayList items1=new ArrayList();  
    String[] itemselected;  
    String itemname;  
    itemselected=request.getParameterValues("Empid");  
    if(itemselected!=null){  
   for(int i=0;i<itemselected.length;i++){  
   itemname=itemselected[i];  
   items.add(itemname);  
  // items1.addAll(items);  
   }  
      
    }  
      
    Iterator iterator=items.iterator();  
        
   
%>

</body>

</html>

Servlet is -:

package mycontroller;
import java.io.IOException;
import java.sql.Connection;
import java.util.Vector;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import mydao.ConnectSQL;
import mydao.DaoException;
import mydao.UserDetails;
import mydao.New_USER;

/**
 * Servlet implementation class for Servlet: RegisterServlet
 *
 */
 
    public class DeleteServlet extends javax.servlet.http.HttpServlet implements javax.servlet.Servlet {
   //static final long serialVersionUID = 1L;
	  
     
       private UserDetails userdetails;
		
		
    /* (non-Java-doc)
	 * @see javax.servlet.http.HttpServlet#HttpServlet()
	 */
          
	   public void init() throws ServletException
	   { 
		   System.out.println("a-- init");
	   }
  	 
	/* (non-Java-doc)
	 * @see javax.servlet.http.HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	   
	   
	protected void doGet(HttpServletRequest request,  HttpServletResponse response) throws ServletException, IOException {
	//	request.getRequestDispatcher("VIEW").forward(request, response);
	
		System.out.println("Inside get");
		New_USER user = new New_USER();
		
	 Object value = request.getAttribute("Empid");
	 if(value==null) {
		 System.out.println("Value is null");
	 }
	 System.out.println(value);
		
				 try {
					 System.out.println("inside try");
					 UserDetails. delete(user);
				} catch (DaoException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				} catch (ClassNotFoundException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
	}
		
	protected void doPost(HttpServletRequest request , HttpServletResponse response) throws ServletException, IOException {
		
				}
				
			
    }

delete method

please suggest what i am doing wrong

Mohamed Inayath

Ranch Hand

Posts: 124

posted 16 years ago

Number of slices to send:

Optional 'thank-you' note:

Send

Nitin,

In your JSP you are populating the values and displaying it.
After that you are trying to get a value from the request object.

Why is the above code in the JSP?

Also in the Delete Servlet you are expecting the value from the below code

Where are you setting the value?

Confusing...! Isn't it?

Ulf Dittmer

Rancher

Posts: 43081

posted 16 years ago

Number of slices to send:

Optional 'thank-you' note:

Send

For starters, having multiple checkboxes all named "Empid" is bound to create problems. Give them distinct names (like Empid1, Empid2, etc.) and see what happens.

Seetharaman Venkatasamy

Ranch Hand

Posts: 5575

I like...

posted 16 years ago

Number of slices to send:

Optional 'thank-you' note:

Send

Ulf Dittmer wrote:For starters, having multiple checkboxes all named "Empid" is bound to create problems.

I Agree with you completely. unless you need to create dynamic check boxes, for starter better to give separate checkbox name

Nitin Belaram

Ranch Hand

Posts: 67

posted 16 years ago

Number of slices to send:

Optional 'thank-you' note:

Send

Mohamed Inayath wrote:Nitin,

In your JSP you are populating the values and displaying it.
After that you are trying to get a value from the request object.
String str=request.getParameter("value");
Why is the above code in the JSP?

Also in the Delete Servlet you are expecting the value from the below code
Object value = request.getAttribute("Empid");

Where are you setting the value?

Confusing...! Isn't it?

Sorry i had put thewrong code MY code is:

i had to delete rows on basic of checkbox
Procedure which i am doing: --
I had a jsp in which on basic of selection of checkbox i am passing empid value to servlet in which do get method is defined which is calling delete () in another java pagewhich is deleting record

sorry i had put thewrong code MY code is:
JSP is : -

<%@page import="java.util.*"%>
<%@page import="java.lang.reflect.Array"%>

<%@page import="mydao.New_USER;"%>
<html>
<head>

<title>Insert title here</title>
</head>
<body> 
  <form Name="Display" Method="get" action="DeleteServlet">

<CENTER> 
    <TABLE   BORDER="3"> 
         <TR> 
       <TH>Select</TH><TH>EmpID</TH><TH>EmpFName</TH><TH>EmpLName</TH><TH>Department</TH><TH>Designation</TH><TH>Email</TH><TH>Address</TH><TH>Project</TH><TH>Manager</TH>  
         </TR> 
 
 <% 
 
 
 
    ArrayList p = new ArrayList (); 
    ArrayList rows = new ArrayList (p); 
 
 if (request.getAttribute("AttributeUser") != null) {
 	
    rows = (ArrayList ) request.getAttribute("AttributeUser");  
    
 for(int i=0; i< rows.size(); i++) { 
 	New_USER user = (New_USER) rows.get(i);
 %>
 		<tr>
 		<td><input type="checkbox" name="Empid" value= <%= user.getEmpid()%> ></td>
 		    
 			<td>  <%= user.getEmpid()%> </td>
 			<td> <%= user.getEmpfname()%>  </td>
 			<td> <%= user.getEmplname()%>  </td>
 			<td> <%= user.getDepartment()%>  </td>
 			<td> <%= user.getDesignation()%>  </td>
 			<td> <%= user.getEmail()%>  </td>
 			<td> <%= user.getAddress()%>  </td>
 			<td> <%= user.getProject()%>  </td>
 			<td> <%= user.getManager()%>  </td>
 			
 		</tr>
 
 <%}}%>
 
 </Table>

<%   
      
   
    ArrayList items=new ArrayList();  
    ArrayList items1=new ArrayList();  
    String[] itemselected;  
    String itemname;  
    itemselected=request.getParameterValues("Empid");  
    if(itemselected!=null){  
   for(int i=0;i<itemselected.length;i++){  
   itemname=itemselected[i];  
   items.add(itemname);  
  // items1.addAll(items);  
   }  
      
    }  
      
    Iterator iterator=items.iterator();  
    
      
   
%>

</body>

</html>

Servlet is :--

package mycontroller;
import java.io.IOException;
import java.sql.Connection;
import java.util.Vector;

/**
 * Servlet implementation class for Servlet: RegisterServlet
 *
 */
 
    public class DeleteServlet extends javax.servlet.http.HttpServlet implements javax.servlet.Servlet {
   //static final long serialVersionUID = 1L;
	  
     
       private UserDetails userdetails;
		
		
    /* (non-Java-doc)
	 * @see javax.servlet.http.HttpServlet#HttpServlet()
	 */
          
	   public void init() throws ServletException
	   { 
		   System.out.println("a-- init");
	   }
  	 
	/* (non-Java-doc)
	 * @see javax.servlet.http.HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	   
	   
	protected void doGet(HttpServletRequest request,  HttpServletResponse response) throws ServletException, IOException {
	//	request.getRequestDispatcher("VIEW").forward(request, response);
	
		System.out.println("Inside get");
		New_USER user = new New_USER();
		
	 Object  value = request.getAttribute("Empid");
	 if(value==null) {
		 System.out.println("Value is null");
	 }
	 System.out.println(value);
		
				 try {
					 System.out.println("inside try");
					 UserDetails. delete(user);
				} catch (DaoException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				} catch (ClassNotFoundException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
	}
		
	protected void doPost(HttpServletRequest request , HttpServletResponse response) throws ServletException, IOException {
		
				}
				
			
    }

delete method code

Object value = request.getAttribute("Empid");
if(value==null) {
System.out.println("Value is null");

I am not getting empid value printed in my servlet .
I am getting Value is null

Seetharaman Venkatasamy

Ranch Hand

Posts: 5575

I like...

posted 16 years ago

Number of slices to send:

Optional 'thank-you' note:

Send

How you will get the value? thats what Mohamed Inayath mentioned earlier

Ulf Dittmer

Rancher

Posts: 43081

posted 16 years ago

Number of slices to send:

Optional 'thank-you' note:

Send

I'm not sure how this code differs -please restrict any code you post to *just the relevant lines*, not close to 200 lines- but you're still creating multiple checkboxes with the same name, and you're still using "getAttribute", when -as Mohamed pointed out- you probably want to use getParameter.

Albareto McKenzie

Ranch Hand

Posts: 312

posted 16 years ago

Number of slices to send:

Optional 'thank-you' note:

Send

Both codes only differ in this lines in JSP:
String str=request.getParameter("value");
System.out.println(" Str" + str);

which are really irrelevant.

Input fields are not Attributes, are Parameters, so, as the other users have told you use getParameter to get the parameter

Nitin Belaram

Ranch Hand

Posts: 67

posted 16 years ago

Number of slices to send:

Optional 'thank-you' note:

Send

seetharaman venkatasamy wrote:How you will get the value? thats what Mohamed Inayath mentioned earlier

I am getting the value in servlet by changing it to
Object value = request.getParameterValues("Empid");
System.out.println(value);

But i am not getting value in delete method , i am getting output as "user not deleted,

Mohamed Inayath

Ranch Hand

Posts: 124

posted 16 years ago

Number of slices to send:

Optional 'thank-you' note:

Send

When are you setting AttributeUser value and where?

With your code, I believe it will be always give null and the empd id never set/displayed either.

Aren't you getting any NUll pointer exception when you access the page very first time?

Albareto McKenzie

Ranch Hand

Posts: 312

posted 16 years ago

Number of slices to send:

Optional 'thank-you' note:

Send

Nitin Belaram wrote:

Object value = request.getParameterValues("Empid");

This code will not compile, you are trying to set to an Object an String[]...

Seetharaman Venkatasamy

Ranch Hand

Posts: 5575

I like...

posted 16 years ago

Number of slices to send:

Optional 'thank-you' note:

Send

Well, in servlet you are just creating the object

where you are setting the value ? you need to set the value using setter method of User and pass into delete()...get there using getter method of User

Hope this helps

Seetharaman Venkatasamy

Ranch Hand

Posts: 5575

I like...

posted 16 years ago

Number of slices to send:

Optional 'thank-you' note:

Send

Albareto McKenzie wrote:
This code will not compile, you are trying to set to an Object an String[]...

ohh... i miss it out

. well done Albareto . you need String[] or Object[]

Albareto McKenzie

Ranch Hand

Posts: 312

posted 16 years ago

Number of slices to send:

Optional 'thank-you' note:

Send

Thanks man

Anyway, I think that if you just try to make a String value= request.getParameter("Empid"); it should return you something, I don't know exactly what, but something, try that and let us know if something appears in your value var

Bear Bibeault

Sheriff

Posts: 67754

173

I like...

posted 16 years ago

Number of slices to send:

Optional 'thank-you' note:

Send

Ulf Dittmer wrote:For starters, having multiple checkboxes all named "Empid" is bound to create problems. Give them distinct names (like Empid1, Empid2, etc.) and see what happens.

I'm going to respectfully disagree with this a general notion. It's fine to have multiple checkboxes with the same name, but different values, when they logically represent a group or the same abstraction.

[Asking smart questions] [About Bear] [Books by Bear]

HTML 5 (verified skill)
Skill verified by Jeanne Boyarsky

CSS 3 (verified skill)
Skill verified by Jeanne Boyarsky

JavaScript (verified skill)
Skill verified by Jeanne Boyarsky