request.getParameter returns null in JSP
Question
Form.jsp
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Form</title>
<body bgcolor="#FFFFFF" text="#000000">
<h1>Please enter your details</h1>
<form name="RegistrationForm" action="NewUser" method="post">
<table cellspacing="5" cellpadding="5" border="1">
<tr>
<td align="right">First Name:</td>
<td><input type="text" name="NewFirstName"></td>
</tr>
<tr>
<td align="right">Last Name:</td>
<td><input type="text" name="NewLastName"></td>
</tr>
<tr>
<td align="right">Email Address:</td>
<td><input type="text" name="EmailAddress"></td>
</tr>
<tr>
<td align="right">Phone Number:</td>
<td><input type="text" name="Phone Number"></td>
</tr>
<tr>
<td align="right">Semester</td>
<td><input type="text" name="Semester"></td>
</tr>
</table>
<input type="submit" value="Submit">
</form>
</body>
</html>
NewUser.java(Servlet Class)
package com.seria.quiz;
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class NewUser
*/
@WebServlet("/NewUser")
public class NewUser extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public NewUser() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
* response)
*/
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
* response)
*/
protected void doPost(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter pw = response.getWriter();
Connection conn = null;
try {
String FirstName = request.getParameter("firstName");
System.out.println("Your firstname: " + FirstName);
String LastName = request.getParameter("lastName");
System.out.println("Your LastName: " + LastName);
String Emailid = request.getParameter("email");
String PhoneNumber = request.getParameter("phoneNumber");
String Semester = request.getParameter("semester");
Class.forName("com.mysql.jdbc.Driver");
conn = DriverManager.getConnection(
"jdbc:mysql://localhost:3306/seriaquiz", "root", "root");
PreparedStatement pst = (PreparedStatement) conn
.prepareStatement("insert into formdetails(firstName,lastName,email,phoneNumber,semester) values(?,?,?,?,?)");// try2
// the
// name
pst.setString(1, FirstName);
System.out.println("Your firstname1: " + FirstName);
pst.setString(2, LastName);
System.out.println("Your LastName1: " + LastName);
pst.setString(3, Emailid);
pst.setString(4, PhoneNumber);
pst.setString(5, Semester);
int i = pst.executeUpdate();
String msg = " ";
if (i != 0) {
msg = "Record has been inserted";
pw.println("<font size='6' color=blue>" + msg + "</font>");
} else {
msg = "failed to insert the data";
pw.println("<font size='6' color=blue>" + msg + "</font>");
}
pst.close();
} catch (Exception e) {
pw.println(e);
}
}
}
As the title says request.getParameter is returning null every time. I put sysout statements after requestParameter, and it shows null value. Any help will be appreciated. Sorry for any inconvenience, I'm new here.
4 answers
solution1
1 ACCPTED 2014-10-07 08:45:11
The parameter names in servlet need to match them in the JSP
so
String FirstName = request.getParameter("firstName");
should be
String FirstName = request.getParameter("NewFirstName");
solution2
0 2014-10-07 08:47:00
您要输入错误的参数，您应该始终要求输入与HTML中所述相同的ID /名称
request.getParameter("NewFirstName");
solution3
0 2014-10-07 09:09:16
From w3.org section 17.2 Controls
Users interact with forms through named controls .
A control's "control name" is given by its name attribute. The scope of the name attribute for a
control within a FORM element is the FORM element.When a form is submitted for processing, some controls have their name paired with their current
value and these pairs are submitted with the form.
Example of control is your
<input type="text" name="NewFirstName">
So when the form gets submitted, it contains a control name=value eg
NewFirstName=YourFirstName
In your JSP, you should do access it using the the control name
String FirstName = request.getParameter("NewFirstName");
solution4
0 2014-10-07 11:39:36
Get the exact value of a form parameter try this....
String FirstName = request.getParameter("NewFirstName");
because ..
you specify name attribute by 'NewFirstName'...
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