Java tryParseInt best practice

Question

I have a lot of code that gathers user input and parses it, I want to parse integer values without throwing exceptions.

My current tryParseInt() function is code is simple:

public static Integer tryParseInt( String text )
{
    if(text == null)
        return null;

    try
    {
        return new Integer( text.trim() );
    }
    catch ( NumberFormatException e )
    {
        return null;
    }
}

But i am getting lots of NumberFormatExceptions and i am worried becouse that may impact my app performance. Can anyone suggest me on best practice for parsing user inputs.

Thank you

If you get a lot of NumberFormatExceptions, clean data from non-numeric symbols before parsing — Max77, Jul 03 '15 at 09:13
There are lots of articles around that topic. I prefer [this one](http://stackoverflow.com/a/1369131/1389444) — Patrik, Jul 03 '15 at 09:48

Madhan · Accepted Answer · 2015-07-03T09:43:32.723

3

You can go with regex as it is more fail proof

 public static Integer tryParseInt(String text) {
    if (text != null && !text.isEmpty()) {
        if (text.trim().matches("[0-9]+")) {
            return Integer.valueOf(text.trim());
        }
    }
    return null;
}

edited Jul 03 '15 at 09:43

answered Jul 03 '15 at 09:21

Madhan

5,750
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1

Good one..I think this will be best approach.. Just FYI "\\d+" can also be written as "[0-9]+" – Viraj Nalawade Jul 03 '15 at 09:30
1

@VirajNalawade Yup.Got more insight from [this](http://stackoverflow.com/questions/16621738/d-is-less-efficient-than-0-9) – Madhan Jul 03 '15 at 09:44
the link is cool.. wasnt aware of it.. – Viraj Nalawade Jul 03 '15 at 10:30

score 2 · Answer 2 · answered Jul 03 '15 at 09:17

2

This is a very helpful experiment and indeed my experience is removing exceptions is better for performance

answered Jul 03 '15 at 09:17

Viraj Nalawade

3,137
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Crazyjavahacking · Answer 3 · 2015-07-03T09:16:57.697

If you are getting a lot of NumberFormatExceptions, you might consider checking the parsing input before the actual parsing.

BTW the return new Integer( text.trim() ); is not very efficient as you will be allocating a lot of unnecessary objects (in the range from -128 to 127).

public static Integer tryParseInt(String text) {
    if(text == null)
        return null;

    try {
        return Integer.valueOf(text.trim());
    }
    catch (NumberFormatException e) {
        return null;
    }
}

Java tryParseInt best practice

3 Answers3