Java Form Validation

[Lovie]

I created a small servlet program with a form asking for User First and Last Name, Gender then hit the Submit button. However I want to validate the form so that if the user does not enter their full name and select a gender then the program should display a message saying the the form is incomplete. I need some help on the validation coding?

[emceenugget]

what do you specifically need help with doing? to validate parameters, you need to get them and then compare them to whatever makes them in/valid.

[Eranga]

Basically you need to validate fields, comparing with the database or a text file is the option you have to take.

[Lovie]

Its like completing a form with mandatory fields. If the user did not enter information into a field eg. last name, they should get a prompt saying, "Please enter your last name". So I need to validate 4 inputs: firstName, lastName, gender: whether Male or Female, or if user hits the Submit button without entering any data at all.

[Lovie]

I wanted to verify where in the program I put the validation codes and should it be another small program or class:

if (firstName != null) {
System.out.println("Please enter first name");
else if (lastName != null) {
System.out.println("Please enter last name");
Else if (firstName == null) && (lastName == null) {
System.out.println("Please enter your first and last name");
etc......

I am not 100% sure that I have the syntax correct with the != or ==

[Eranga]

Validation is depends on your application design.

The way you workout is not bad. But the thing is not in standard. Say you entered a number as the first name, still it's valid. Because you just check is for null value. Same for other fields as well.

[dyapasrikanth]

try to use java script
<script>
function x()
{
if(-)
return true
else
return false
}
</script>
<form action="/asf" method="get" onsubmit="return x()"
---
</form>

[dyapasrikanth]

try to use java script
<script>
function x()
{
if(-)
return true
else
return false
}
</script>
<form action="/asf" method="get" onsubmit="return x()">
---
</form>