JTextField That Accept Only Integer Input?

Jul 5, 2014

I have a GUI with a JTextField. I need to check that the input entered by the user is made up of only integers.

For example I accept: 1, 10, 530, ...

I do not accept: -10, 1.5, -6 ...

I would like to implement this control by using a regular expression so I would have a code like that.

JTextField text = new JTextField();
String input = text.getText();
boolean bool = checkInteger(input);
if(bool)
System.out.println("Ok");
else
System.out.println("Error");

The checkInteger(String input) method should check if the input string is correct or not.

How can I do to implement this control with regular expressions?

Is there an easier way to do it?

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import java.util.Scanner;
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int number;
public static void main(String[] args) {
Scanner input = new Scanner(System.in);

[Code] ....

I know the message is not being printed from the Main method. I'm not sure how to do that.

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*/
 package numbersum;
import java.util.*; 
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/**
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It works if I enter 1234567891 (10 digits)
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digit: 2
digit: 3
digit: 4
digit: 5
digit: 6
digit: 7
digit: 8
digit: 9
digit: 1

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But if I enter 11 digits, it fails:

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at java.util.Scanner.nextInt(Scanner.java:2123)
at java.util.Scanner.nextInt(Scanner.java:2076)
at week4numbersum.Week4NumberSum.main(Week4NumberSum. java:26)

java - Scanner error with nextInt() - Stack Overflow gives me some infor for InputMismatchException - which I find described as In order to deal with this exception you must verify that the input data of your application meet its specification. When this error is thrown, the format of the input data is incorrect and thus, you must fix it, in order for your application to proceed its execution.

I don't understand why the 10 digit integer is OK but the 11 or > digit integer is a mismatch.

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Examples:

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package example;

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