Coverting String to LocalTime with/without nanoOfSeconds

I need to convert a string to LocalTime (java-8 not joda) that may or maynot have nanoOfSeconds in the string. The String format is in the form of 07:06:05 or 07:06:05.123456 The string may or may not have a decimal place in the seconds and when it does there could be any number of characters to represent the Nano Seconds part.

Using a DateTimeForamtter such as

DateTimeFormatter dtf = DateTimeFormatter.ofPattern("H:mm:ss");

or

DateTimeFormatter dtf = DateTimeFormatter.ofPattern("H:mm:ss.SSSSSS");

I can use an IF statement to distinguish between the two formats such as:

DateTimeFormatter dtf;
if (time1.contains(".") {
   dtf = DateTimeFormatter.ofPattern("H:mm:ss.SSSSSS);
} else {
   dtf = DateTimeFormatter.ofPattern("H:mm:ss);
}

This works fine and I'm OK with this but I need to be able to also use a varying number of positions after the decimal point.

A sample data set might be:

[11:07:59.68750, 11:08:00.781250, 11:08:00.773437500, 11:08:01]

Is there a way to allow the formatter to parse any number of digits after the decimal without it throwing a java.time.format.DateTimeParseException when the number of decimal places is unknown?

I'm hoping I missing something really simple.