import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Example {
public static void main(String[] args) {
final String regex = "(?<year>[\\d]{4})-(?<month>0[1-9]|1[1-2])-(?<day>0[1-9]|[1-2][0-9]|3[0-1])T(?<hour>[0-1][0-9]|2[0-3]):(?<minute>[0-5][0-9]):(?<second>[0-5][0-9])(?:Z|.(?<millisecond>[0-9]{2,3}))";
final String string = "2021-03-31T19:52:52.01\n"
+ "2021-03-31T19:52:52Z\n"
+ "2021-11-31T19:52:52.010\n"
+ "2021-12-31T19:52:52Z\n"
+ "2021-12-31T23:52:52Z";
final Pattern pattern = Pattern.compile(regex, Pattern.MULTILINE | Pattern.CASE_INSENSITIVE);
final Matcher matcher = pattern.matcher(string);
while (matcher.find()) {
System.out.println("Full match: " + matcher.group(0));
for (int i = 1; i <= matcher.groupCount(); i++) {
System.out.println("Group " + i + ": " + matcher.group(i));
}
}
}
}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Java, please visit: https://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html