Convert string to int with 1st null saving

Question

Usually Integer.valueOf(), Integer.parseInt() works perfect. But i have problem if in a String object are some nulls(0), here is some code.

StringBuilder sb = new StringBuilder();

    sb.append("0");
    sb.append(9);

    Integer afterConvert = Integer.valueOf(sb.toString());
    System.out.println(afterConvert);

This code shows "9", but i need "09". Is any way to achieve it?

Why do you need "09" as an integer? it doesn't even an integer! — BobTheBuilder, Dec 16 '13 at 07:14
You can't have "09" in an `Interger` variable, but in a `String`! So you have to format the output. — A4L, Dec 16 '13 at 07:14
Side note, integers starting with `0` are octal representations, so you cannot assign an int variable with value `09` directly. A decimal integer with value `9` **should** be represented as `9`. — Mena, Dec 16 '13 at 07:14
Check this post http://stackoverflow.com/questions/8023699/java-how-to-format-a-number-to-a-2-char-string — Merlin, Dec 16 '13 at 07:15
Why aren't you just doing `System.out.println(sb);` on the last line? — Dawood ibn Kareem, Dec 16 '13 at 07:16
After Integer.valueOf the knowledge about leading zeroes is gone. You'll need to keep the string or if you know how many zeroes there are you can format according during output. — Werner Henze, Dec 16 '13 at 10:29

score 2 · Accepted Answer · edited May 23 '17 at 12:19

2

This has nothing to do with null values.

The Integer value of 09 is 9.

If you want to print leasing zeros, use:

System.out.println(String.format("%02d", afterConvert));

See similar question here.

edited May 23 '17 at 12:19

Community

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answered Dec 16 '13 at 07:12

BobTheBuilder

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as i understand that is way for DISPLAYING "09", but in fact afterConvert has "9" value? – Artem Ruchkov Dec 16 '13 at 07:29
You are right. There is no meaning for integer to be 09, it can only be 9. – BobTheBuilder Dec 16 '13 at 07:34

score 0 · Answer 2 · answered Dec 16 '13 at 07:13

0

You cannot print Integer with leading 0s like this. You can use NumberFormat class:

NumberFormat nb = NumberFormat.getInstance();
nb.setMinimumFractionDigits(2);
System.out.println(nb.format(afterConvert));

answered Dec 16 '13 at 07:13

dzielins42

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Convert string to int with 1st null saving

2 Answers2