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Java Program to validate if a String contains only numbers
To validate if a String has only numbers, you can try the following codes. We have used the matches() method in Java here to check for number in a string.
Example
public class Demo {
public static void main(String []args) {
String str = "978";
System.out.println("Checking for string that has only numbers...");
System.out.println("String: "+str);
if(str.matches("[0-9]+") && str.length() > 2)
System.out.println("String has only numbers!");
else
System.out.println("String consist of characters as well!");
}
}Output
Checking for string that has only numbers... String: 978 String has only numbers!
Let us see another example, wherein our string has numbers as well as characters.
Example
public class Demo {
public static void main(String []args) {
String str = "s987jyg";
System.out.println("Checking for string that has only numbers...");
System.out.println("String: "+str);
if(str.matches("[0-9]+") && str.length() > 2)
System.out.println("String has only numbers!");
else
System.out.println("String consist of characters as well!");
}
}Output
Checking for string that has only numbers... String: s987jyg String consist of characters as well!
Updated on: 26-Jun-2020
1K+ Views
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