Question

I hope to write a small method to do the following things:
For example, the string a = “a123”, then the method should return fulse;
the string b = “111”, it should return true.
It means only the string is an int, it should return true, all the other cases should return false.
Does anyone can help me? Thank you!

Answer 1

You can use Integer.parseInt(integerString);

public boolean isInteger(String integerString){

   try{
      Integer.parseInt(integerString);
      return true;
   } catch (NumberFormatException nfe) {
      return false;
   }
}

a NumberFormatException means parsing will not be successful hence the String is not an integer.