Possible Duplicate:
Java: Good way to encapsulate Integer.parseInt()
how to convert a string to float and avoid using try/catch in java?
C# has Int.TryParse: Int32.TryParse Method (String, Int32%)
The great thing with this method is that it doesn't throw an exception for bad data.
In java, Integer.parseInt("abc")
will throw an exception, and in cases where this may happen a lot performance will suffer.
Is there a way around this somehow for those cases where performance is an issue?
The only other way I can think of is to run the input against an regex, but I have to test to see what is faster.
This question is related to
java
Edit -- just saw your comment about the performance problems associated with a potentially bad piece of input data. I don't know offhand how try/catch on parseInt compares to a regex. I would guess, based on very little hard knowledge, that regexes are not hugely performant, compared to try/catch, in Java.
Anyway, I'd just do this:
public Integer tryParse(Object obj) {
Integer retVal;
try {
retVal = Integer.parseInt((String) obj);
} catch (NumberFormatException nfe) {
retVal = 0; // or null if that is your preference
}
return retVal;
}
No. You have to make your own like this:
boolean tryParseInt(String value) {
try {
Integer.parseInt(value);
return true;
} catch (NumberFormatException e) {
return false;
}
}
...and you can use it like this:
if (tryParseInt(input)) {
Integer.parseInt(input); // We now know that it's safe to parse
}
EDIT (Based on the comment by @Erk)
Something like follows should be better
public int tryParse(String value, int defaultVal) {
try {
return Integer.parseInt(value);
} catch (NumberFormatException e) {
return defaultVal;
}
}
When you overload this with a single string parameter method, it would be even better, which will enable using with the default value being optional.
public int tryParse(String value) {
return tryParse(value, 0)
}
Apache Commons has an IntegerValidator class which appears to do what you want. Java provides no in-built method for doing this.
See here for the groupid/artifactid.
Source: Stackoverflow.com