Find out Integers in String

Question

Hi all:
I am stuck with a simple problem here. I have a file where there are 2 data types String(Item_Name) and int(Item_Code). Something like this: ----------------------------------------------------
  Item_Code            |          Item_Name  |
     34                                  Pens
       7                                   Ice Cream
---------------------------------------------------- Now, I can catch the error if users input character in Item_code like '34ab' with NumberFormatException but how to catch if they put digits in Item_Name like 'Pen345s' ?
Should I first use string tokenizer to divide the strings and then check by individual characters? How to know if its a digit?
thanks in advance.

Answer 1

However if the question was what I had thought it was
then I am right and you are wrong. Catching the
exception IS the right thing to do.
Because of overflow.Here's the code for Integer.parseInt() from the JDK 5.0 source. You can avoid the overhead of catching an exception if you code a simple isNumeric() function. As you can see, they iterate over each character in the string and check if it's a digit.
By the way, most code I've written simple just catch the exception :)
public static int parseInt(String s, int radix)
          throws NumberFormatException
        if (s == null) {
            throw new NumberFormatException("null");
     if (radix < Character.MIN_RADIX) {
         throw new NumberFormatException("radix " + radix +
                             " less than Character.MIN_RADIX");
     if (radix > Character.MAX_RADIX) {
         throw new NumberFormatException("radix " + radix +
                             " greater than Character.MAX_RADIX");
     int result = 0;
     boolean negative = false;
     int i = 0, max = s.length();
     int limit;
     int multmin;
     int digit;
     if (max > 0) {
         if (s.charAt(0) == '-') {
          negative = true;
          limit = Integer.MIN_VALUE;
          i++;
         } else {
          limit = -Integer.MAX_VALUE;
         multmin = limit / radix;
         if (i < max) {
          digit = Character.digit(s.charAt(i++),radix);
          if (digit < 0) {
              throw NumberFormatException.forInputString(s);
          } else {
              result = -digit;
         while (i < max) {
          // Accumulating negatively avoids surprises near MAX_VALUE
          digit = Character.digit(s.charAt(i++),radix);
          if (digit < 0) {
              throw NumberFormatException.forInputString(s);
          if (result < multmin) {
              throw NumberFormatException.forInputString(s);
          result *= radix;
          if (result < limit + digit) {
              throw NumberFormatException.forInputString(s);
          result -= digit;
     } else {
         throw NumberFormatException.forInputString(s);
     if (negative) {
         if (i > 1) {
          return result;
         } else {     /* Only got "-" */
          throw NumberFormatException.forInputString(s);
     } else {
         return -result;
    }