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GET method working but POST method not working

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posted 16 years ago

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Hi,

I'm implementing a simple web application.
I've a jsp page. In the FORM tag I've defined action of my servlet class and method as POST.
The form contains two text fields and a submit button.

In my servlet, I'm doing request.getParameter(<<text field name>>

.

If I'm using GET method, I get the values entered in the text fields.
However, if I'm using POST method, I get null values.

Can anyone pls help me out with a solution for same.

Thanks in advance.

I'm using Tomcat5 webserver.

regards,
Lalit

Ulf Dittmer

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Posts: 43081

posted 16 years ago

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Are the doGet and doPost methods in the servlet any different, or are they using the same code?

Lalit Bansal

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Posts: 63

posted 16 years ago

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I've written the login (of retrieving parameters) in doPost method.
In doGet I'm calling the doPost method by passing request and response objects.

package com.shell.java.actions;
 
import java.io.IOException;
 
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
 
import com.shell.java.dao.LoginDAO;
import com.shell.java.dto.EmployeeDetailsDTO;
import com.shell.java.vo.LoginVO;
 
/**
 * Servlet implementation class for Servlet: LoginAction
 * 
 */
public class LoginAction extends javax.servlet.http.HttpServlet implements
javax.servlet.Servlet {
/*
 * (non-Java-doc)
 * 
 * @see javax.servlet.http.HttpServlet#HttpServlet()
 */
public LoginAction() {
super();
}
 
/*
 * (non-Java-doc)
 * 
 * @see javax.servlet.http.HttpServlet#doGet(HttpServletRequest request,
 *      HttpServletResponse response)
 */
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
System.out.println("Inside Login Action....");
System.out.println(request.getAttribute("empId"));
System.out.println(request.getAttribute("loginPwd"));
LoginVO loginVO = new LoginVO();
loginVO.setEmpId(request.getParameter("empId"));
loginVO.setLoginPwd(request.getParameter("loginPwd"));
 
LoginDAO loginDAO = new LoginDAO();
EmployeeDetailsDTO employeeDetailsDTO = loginDAO
.validateEmpAndGetEmpDetails(loginVO);
RequestDispatcher dispatcher = null;
 
String returnMessage = employeeDetailsDTO.getReturnMessage();
 
if (("loginSuccess").equalsIgnoreCase(returnMessage)) {
dispatcher = request.getRequestDispatcher("index.jsp");
HttpSession session = request.getSession();
session.setAttribute("employeeDetailsDTO", employeeDetailsDTO);
} else if (("loginFailure").equalsIgnoreCase(returnMessage)) {
dispatcher = request.getRequestDispatcher("loginError.jsp");
} else {
dispatcher = request.getRequestDispatcher("systemError.jsp");
}
 
System.out.println("exit action");
 
dispatcher.forward(request, response);
 
}
 
/*
 * (non-Java-doc)
 * 
 * @see javax.servlet.http.HttpServlet#doPost(HttpServletRequest request,
 *      HttpServletResponse response)
 */
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
 
doGet(request, response);
}
}

<html>
 

 
<head>
</head>
 

 

 
<BODY link="#333333" alink="#333333" vlink="#333333" bgColor="#ffffff"
leftMargin="0" topMargin="0" marginwidth="0" marginheight="0">
 

<form method="get" action="LoginAction" enctype="text/plain"
name="loginForm">
<table width="100%" border="0" cellpadding="3" cellspacing="1">
<tr>
<td width="30%"></td>
<td align="left" valign="bottom" width="15%"><font
style="font-size: 13px" color="#000000" face="Arial"> <br>
<br>
<b>Employee Id :</b></font></td>
<td align="left" valign="bottom" width="55%"><input type="text"
size="16" name="empId"></td>
</tr>
<tr>
<td width="30%"></td>
<td align="left" valign="bottom" width="15%"><font
style="font-size: 13px" color="#000000" face="Arial"> <br>
<br>
<b>Password:</b> </font></td>
<td align="left" valign="bottom" width="55%"><input
type="password" size="16" name="loginPwd"></td>
</tr>
</table>
 
<br>
<input type="hidden" name="sourcePage" value="loginPage">
 
<table width="92%" border="0" cellpadding="2" cellspacing="12">
<tr>
<td></td>
<td align="right" valign="middle" width="50%"><input
type="submit" name="loginSubmit" value="Submit"></td>
<td align="left" valign="middle" width="50%"><input
type="reset" name="loginReset" value="Reset"></td>
</tr>
</table>

</form>

</body>

 
</html>

Lalit Bansal

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Posts: 63

posted 16 years ago

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Pls excuse me for putting incorrect servlet code.
The code is as follows:

package com.shell.java.actions;
 
import java.io.IOException;
 
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
 
import com.shell.java.dao.LoginDAO;
import com.shell.java.dto.EmployeeDetailsDTO;
import com.shell.java.vo.LoginVO;
 
/**
 * Servlet implementation class for Servlet: LoginAction
 * 
 */
public class LoginAction extends javax.servlet.http.HttpServlet implements
javax.servlet.Servlet {
/*
 * (non-Java-doc)
 * 
 * @see javax.servlet.http.HttpServlet#HttpServlet()
 */
public LoginAction() {
super();
}
 
/*
 * (non-Java-doc)
 * 
 * @see javax.servlet.http.HttpServlet#doGet(HttpServletRequest request,
 *      HttpServletResponse response)
 */
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
System.out.println("Inside Login Action....");
System.out.println(request.getAttribute("empId"));
System.out.println(request.getAttribute("loginPwd"));
LoginVO loginVO = new LoginVO();
loginVO.setEmpId(request.getParameter("empId"));
loginVO.setLoginPwd(request.getParameter("loginPwd"));
 
LoginDAO loginDAO = new LoginDAO();
EmployeeDetailsDTO employeeDetailsDTO = loginDAO
.validateEmpAndGetEmpDetails(loginVO);
RequestDispatcher dispatcher = null;
 
String returnMessage = employeeDetailsDTO.getReturnMessage();
 
if (("loginSuccess").equalsIgnoreCase(returnMessage)) {
dispatcher = request.getRequestDispatcher("index.jsp");
HttpSession session = request.getSession();
session.setAttribute("employeeDetailsDTO", employeeDetailsDTO);
} else if (("loginFailure").equalsIgnoreCase(returnMessage)) {
dispatcher = request.getRequestDispatcher("loginError.jsp");
} else {
dispatcher = request.getRequestDispatcher("systemError.jsp");
}
 
System.out.println("exit action");
 
dispatcher.forward(request, response);
 
}
 
/*
 * (non-Java-doc)
 * 
 * @see javax.servlet.http.HttpServlet#doPost(HttpServletRequest request,
 *      HttpServletResponse response)
 */
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
 
doPost(request, response);
}
}

Seetharaman Venkatasamy

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posted 16 years ago

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Hi,

i am not sure,inside your post method...

your testing the textbox value..using
System.out.println(request.getAttribute("empId"));System.out.println(request.getAttribute("loginPwd"));

use--- request.getParameter("textbox_name");

thanks & regards,
seetharaman

Lalit Bansal

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Posts: 63

posted 16 years ago

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I've tried with request.getParameter() also. But still the POST method gives null values.

Ulf Dittmer

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Posts: 43081

posted 16 years ago

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The fact that this class has a constructor is suspicious - servlets should not have an explicit constructor, nor should any of your code be calling it.
[ April 29, 2008: Message edited by: Ulf Dittmer ]

Lalit Bansal

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Posts: 63

posted 16 years ago

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I'm using Eclipse 3.3.2 IDE.

The servlet stub code was generated automatically from it. I've just implemented my logic in the doPOST method.

sudhir nim

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Posts: 212

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posted 16 years ago

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Constructor is not the actual problem.

Can you post the code which is working for you ?

[Servlet tutorial] [Servlet 3.0 Cook Book]

Rodrigo Tomita

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Posts: 70

posted 16 years ago

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Originally posted by Lalit Bansal:
I've tried with request.getParameter() also. But still the POST method gives null values.

OK. But just to be clear, you do know the difference between request.getParameter() and request.getAttribute(), right? For form input boxes, it should be getParameter().

I'm just asking because, as Seetharam mentioned, you are printing getAttribute() and using getParameter() later:

Regards.

Lalit Bansal

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Posts: 63

posted 16 years ago

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Pls excuse me for a long post. As becuase there was a bit of confusion in the forum because I'd posted incorrect code earlier, I'm posting both the code - which does not work(i.e., code using POST method) and which works (i.e., code using GET method)

CODE THAT

DOES NOT

WORK

doPost(request, response);
 
}
 
/*
 * (non-Java-doc)
 * 
 * @see javax.servlet.http.HttpServlet#doPost(HttpServletRequest request,
 *      HttpServletResponse response)
 */
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
 
System.out.println("Inside Login Action....");
System.out.println(request.getParameter("empId"));
System.out.println(request.getParameter("loginPwd"));
LoginVO loginVO = new LoginVO();
loginVO.setEmpId(request.getParameter("empId"));
loginVO.setLoginPwd(request.getParameter("loginPwd"));
 
LoginDAO loginDAO = new LoginDAO();
EmployeeDetailsDTO employeeDetailsDTO = loginDAO
.validateEmpAndGetEmpDetails(loginVO);
RequestDispatcher dispatcher = null;
 
String returnMessage = employeeDetailsDTO.getReturnMessage();
 
if (("loginSuccess").equalsIgnoreCase(returnMessage)) {
dispatcher = request.getRequestDispatcher("index.jsp");
HttpSession session = request.getSession();
session.setAttribute("employeeDetailsDTO", employeeDetailsDTO);
} else if (("loginFailure").equalsIgnoreCase(returnMessage)) {
dispatcher = request.getRequestDispatcher("loginError.jsp");
} else {
dispatcher = request.getRequestDispatcher("systemError.jsp");
}
 
System.out.println("exit action");
 
dispatcher.forward(request, response);

}
}

CODE THAT WORKS

package com.shell.java.actions;
 
import java.io.IOException;
 
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
 
import com.shell.java.dao.LoginDAO;
import com.shell.java.dto.EmployeeDetailsDTO;
import com.shell.java.vo.LoginVO;
 
/**
 * Servlet implementation class for Servlet: LoginAction
 * 
 */
public class LoginAction extends javax.servlet.http.HttpServlet implements
javax.servlet.Servlet {
/*
 * (non-Java-doc)
 * 
 * @see javax.servlet.http.HttpServlet#HttpServlet()
 */
public LoginAction() {
super();
}
 
/*
 * (non-Java-doc)
 * 
 * @see javax.servlet.http.HttpServlet#doGet(HttpServletRequest request,
 *      HttpServletResponse response)
 */
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
 
System.out.println("Inside Login Action....");
System.out.println(request.getParameter("empId"));
System.out.println(request.getParameter("loginPwd"));
LoginVO loginVO = new LoginVO();
loginVO.setEmpId(request.getParameter("empId"));
loginVO.setLoginPwd(request.getParameter("loginPwd"));
 
LoginDAO loginDAO = new LoginDAO();
EmployeeDetailsDTO employeeDetailsDTO = loginDAO
.validateEmpAndGetEmpDetails(loginVO);
RequestDispatcher dispatcher = null;
 
String returnMessage = employeeDetailsDTO.getReturnMessage();
 
if (("loginSuccess").equalsIgnoreCase(returnMessage)) {
dispatcher = request.getRequestDispatcher("index.jsp");
HttpSession session = request.getSession();
session.setAttribute("employeeDetailsDTO", employeeDetailsDTO);
} else if (("loginFailure").equalsIgnoreCase(returnMessage)) {
dispatcher = request.getRequestDispatcher("loginError.jsp");
} else {
dispatcher = request.getRequestDispatcher("systemError.jsp");
}
 
System.out.println("exit action");
 
dispatcher.forward(request, response);
 
}
 
/*
 * (non-Java-doc)
 * 
 * @see javax.servlet.http.HttpServlet#doPost(HttpServletRequest request,
 *      HttpServletResponse response)
 */
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
 
doGet(request, response);
 
}
}

[ UD: Removed the HTML from both examples, because -being unformatted in a single line- it screwed up the layout. Please be careful to post formatted code only, and check the layout after posting. ]
[ April 29, 2008: Message edited by: Ulf Dittmer ]

Ulf Dittmer

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Posts: 43081

posted 16 years ago

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So are there any differences between these two codes except for the method names?

Amit Ghorpade

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posted 16 years ago

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Well I am not so much experienced as Ulf and Ben, so with due respect to their posts I would just like to suggest that check if the form that the servlet gets data from, uses POST method to submit data.

Hope this helps

SCJP, SCWCD.
|Asking Good Questions|

Ulf Dittmer

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posted 16 years ago

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check if the form that the servlet gets data from, uses POST method to submit data.

Well, we could have checked that until I deleted the complete HTML from the previous post :-) Sorry, had to be done - it made this topic completely unreadable.

But it's unlikely to be the problem - as far as the getParameter method is concerned, there is no difference between GET and POST.

Lalit Bansal

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Posts: 63

posted 16 years ago

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Ulf,

There are no differences in the code except the method names.

When my html request is GET type, I get the values of input fields.
But when request is POST type, I get null values.

Amit : Form uses GET method when call in servlet is to doGet Method
Form uses POST method when call in servlet is to doPost Method

Is this issue anything related with server I'm using?

Dharmender Singh Singh

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posted 16 years ago

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you have to remove the attribute (enctype="text/plain") from your jsp/html page from the <form> tag, to work fine. after removing try the application it wil certainly work.

Lalit Bansal

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Posts: 63

posted 16 years ago

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Hi Dharmendra,

Thanks very much. It does work with your solution.

Any reason(s) for such behavior ?

Ben Souther

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posted 16 years ago

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The default encoding for an HTTP post request (what your servlet is expecting) is application/x-www-form-urlencoded; not text/plain.

Nice catch by Dharmender Singh Singh.

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