Java 11 (Zulu) 中的 DateTimeFormatter 不适用于 AM / PM 格式

Question

I am trying to convert a String representing a time in AM/PM format to java.sql.Time, but I get a DateTimeParseException:

public static java.sql.Time getTimeValue(String valStr) {
    if (valStr == null || valStr.isEmpty()) {
        return null;
    }
    DateTimeFormatter dateTimeFormatter;
    if (valStr.toUpperCase().endsWith("AM") || valStr.toUpperCase().endsWith("PM")) {
        dateTimeFormatter = DateTimeFormatter.ofPattern("h:mm a");
    } else {
        dateTimeFormatter = DateTimeFormatter.ofPattern("HH:mm");
    }
    try {
        return java.sql.Time.valueOf(LocalTime.parse(valStr, dateTimeFormatter));
    } catch (Exception ex) {
        return null;
    }
}

For an input value of "7:16 PM" I get the following exception:

java.time.format.DateTimeParseException: Text '7:16 PM' could not be parsed at index 5
at java.base/java.time.format.DateTimeFormatter.parseResolved0(DateTimeFormatter.java:2046)
at java.base/java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1948)
at java.base/java.time.LocalTime.parse(LocalTime.java:463)
at ...getTimeValue(....java:864)

I am using Java 11.0.5, Zulu 11.35.15 for 64-bits.

Does anyone have any idea on why this isn't working? I have no problems with the same piece of code in Java 8.

I have checked the value of the DateTimeFormatter and it is the one corresponding to the "h:mm a" pattern.

Answer 1

Thanks a lot John Skeet and Robert, indeed, it was a Locale problem.

• In my minimal example, everything worked as expected, but that was because I had US Locale.
• In the production code, the Locale were from German where it seems that AM/PM does not exist at all. The format of the date came from an external device which was exporting the information into our application.

The solution was to always create the DateTimeFormatter with the Locale.US argument, so everything works as expected now.

if (valStr.toUpperCase().endsWith("AM") || valStr.toUpperCase().endsWith("PM")) {
  dateTimeFormatter = DateTimeFormatter.ofPattern("h:mm a", Locale.US);
} else {
  dateTimeFormatter = DateTimeFormatter.ofPattern("HH:mm");
}