how to test an integer?

Hi,
I have a textbox in html. I am using a post method in it. When the value is recieved by the servlet, I want to test whether the value recieved from the textbox is a number or not.

Integer.parseInt(request.getParameter("textbex1"))
would give an error if the user has not entered a valid number.

Does anybody know the solution?
I will be grateful for the solution

Thanks in advance.
Monika

Monika,

You are correct in using the Integer.parseInt() method. To see if the String you passed it is a number, use the throw and catch exception handling for this method.

In other words:
// the integer
int number = 0;
// the string
String theString = "Two";
// the try block
try {
// parse the string and store in number
number = Integer.parseInt(theString);
}catch(java.lang.NumberFormatException e) {
// this code is executed if there was an error parsing the String
System.out.println("The String is not a number!");
}


Hope this helps!

Regards,

dogBear

PS Please Rate this Response!!!!

Hi,
Thanks a lot for your reply.
But I don't want to throw an exception. I just want to test if it is number or not. The solution could be in java or javascript.
Bye,
Monika

Monika,

If you don't want to throw an exception, then simply test each character in the String, like so:

// the String holding the text
String theNumber = "25";
// the sentinel
boolean isANumber = true;
// loop through each character in the String
// notice that we're testing for two things:
// 1) index remains in bounds
// 2) isANumber remains true
for ( int index = 0 ; index < theNumber.length() && isANumber ; index++ )
if ( theNumber.charAt(index) < '0' || theNumber.charAt(index) > '9' )
isANumber = false;

// do the result printout...
if ( isANumber )
System.out.println("This is a number!");
else
System.out.println("This is NOT a number!");



Is this more what you're looking for?

Regards,

dogBear

PS Please Rate this Response!!!!