I am trying to validate a string whether it is in ISO-8601 date or not, but it is throwing a parse exception, not sure where it is going wrong.
try {
String s = "2007-03-01T13:00:00Z";
SimpleDateFormat ft = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZ");
ft.setLenient(false);
System.out.println(ft.format(ft.parse(s)));
} catch (ParseException e) {
System.out.println(e.getMessage());
}
output is:
Unparseable date: "2007-03-01T10:00:00Z"
I suspect that Z is being interpreted as a time zone so would match -0800 but not a literal Z so you could solve that by quoting: 'Z'.
getErrorOffset should tell you where the problem is.
Z for the timezone, but there are also valid ISO 8601 date strings where the timezone is something else than Z - so the validation wouldn't work for all valid ISO 8601 date strings.
replaceLast("Z$", "+0:00") or rely on the Java7 pattern that you noted.If you're using Java 7, use the following format string: "yyyy-MM-dd'T'HH:mm:ssXXX"
Note: X is a new code (added in Java 7) that matches ISO 8601 time zone strings; see the API documentation of SimpleDateFormat.
If you want to validate an arbitrary string, you cannot hardcode the "Z" time zone designator, as the validation would fail for a valid ISO8601 time stamp like e.g. "2007-03-01T13:00:00+01".
If you are using Java 6 or earlier, SimpleDateFormat will not support ISO8601 time zone encoding, so you cannot use it to validate time stamps either. With Java 7 or later, you can use new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssX");.
Your code does not work because the SDF is very limited ad was not aware of ISO 8601 at the time when it was written.
You can take this code:
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import org.apache.commons.lang.time.DateUtils;
public final class JSONDateUtil {
private static final DateFormat ISO8601_FORMAT = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
static {
ISO8601_FORMAT.setLenient(false);
ISO8601_FORMAT.setTimeZone(DateUtils.UTC_TIME_ZONE);
}
public static String toJSON(Date date) {
return ISO8601_FORMAT.format(date);
}
public static String toJSON(long millis) {
return ISO8601_FORMAT.format(millis);
}
public static Date toJava(String date) {
try {
return ISO8601_FORMAT.parse(date);
} catch (ParseException e) {
return null;
}
}
}
Note the timezone, very important.
ISO8601_FORMAT.setTimeZone(DateUtils.UTC_TIME_ZONE);SimpleDateFormat, the code X, which matches the ISO 8601 time zone.
FYI, if you used Joda-Time instead of the notoriously troublesome java.util.Date/Calendar classes, you could simply pass that ISO 8601 string straight into a DateTime constructor without the bother of a formatter. Joda-Time uses ISO 8601 as its defaults.
DateTimeZone timeZone = DateTimeZone.forID( "America/Montreal" );
DateTime dateTime = new DateTime( "2007-03-01T13:00:00Z", timeZone );
To determine if your input string was invalid, catch IllegalArgumentException.
You can even get a java.util.Date back out if need be.
java.util.Date date = dateTime.toDate();
HH:mm:ss'Z'")?