Making a String accept only letters ( no numbers ).

Question

Is it possible to allow only letters or numbers in a string in java ? for example :

String Text;
Text = jTextField1.getText();

now

if (Text is a number) {System.out.println("Invalid Input");}

Hint: Stick to common naming conventions and make fields and variables lowercase (i.e. `Text` in your case). — Howard, Jun 17 '12 at 11:29
Please have a look at this [example](http://stackoverflow.com/questions/9477354/how-to-allow-introducing-only-digits-in-jtextfield/9478124#9478124), also, simply replace `if (Character.isDigit(text.charAt(len - 1)))` with `if (!Character.isDigit(text.charAt(len - 1)))` and I guess it will work for your scenario as well :-) — nIcE cOw, Jun 17 '12 at 12:40

score 10 · Accepted Answer · edited May 23 '17 at 11:45

10

you have two choices to use

JFormattedTextField with proper Formatter or InputVerifier
use DocumentFilter

notice don't use String Text; (possible reserved word for API name or its method) use String text; more in the Naming convention

edited May 23 '17 at 11:45

Community

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answered Jun 17 '12 at 11:23

mKorbel

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score 1 · Answer 2 · answered Nov 09 '12 at 12:54

1

Addition: You could do it also like the following, though i recommend mKorbel's answer.

try  {
    System.out.println(Integer.parseInt(Text) + "is a valid input.");
} catch (Exception e) {
    System.out.println("The input "+ Text + "is invalid");
}

answered Nov 09 '12 at 12:54

shidizzle

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Making a String accept only letters ( no numbers ).

2 Answers2