无法从 TemporalAccessor 获取 LocalTime

Question

我对 Java 8 还很陌生，所以这个问题可能有一个明显的答案，但在阅读了其他类似的 SO 问题后，我找不到任何导致我的问题的相似之处。

这是我的班级：

import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.Locale;

public class LocalDateTimeIssue {

    public static void main(String[] args) {
        String dateTimeString = "18-04-2019 12:14:46";
        DateTimeFormatter dtf = DateTimeFormatter.ofPattern("dd-MM-yyyy hh:mm:ss", Locale.US);
        LocalDateTime ldt = LocalDateTime.parse(dateTimeString , dtf);
        System.out.println(ldt.getSecond());
    }

}

这会引发以下异常：

Exception in thread "main" java.time.format.DateTimeParseException: Text '18-04-2019 12:14:46' could not be parsed: Unable to obtain LocalDateTime from TemporalAccessor: {MilliOfSecond=0, MinuteOfHour=14, HourOfAmPm=0, NanoOfSecond=0, MicroOfSecond=0, SecondOfMinute=46},ISO resolved to 2019-04-18 of type java.time.format.Parsed
    at java.time.format.DateTimeFormatter.createError(DateTimeFormatter.java:1920)
    at java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1855)
    at java.time.LocalDateTime.parse(LocalDateTime.java:492)
    at LocalDateTimeIssue.main(LocalDateTimeIssue.java:10)
Caused by: java.time.DateTimeException: Unable to obtain LocalDateTime from TemporalAccessor: {MilliOfSecond=0, MinuteOfHour=14, HourOfAmPm=0, NanoOfSecond=0, MicroOfSecond=0, SecondOfMinute=46},ISO resolved to 2019-04-18 of type java.time.format.Parsed
    at java.time.LocalDateTime.from(LocalDateTime.java:461)
    at java.time.format.Parsed.query(Parsed.java:226)
    at java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1851)
    ... 2 more
Caused by: java.time.DateTimeException: Unable to obtain LocalTime from TemporalAccessor: {MilliOfSecond=0, MinuteOfHour=14, HourOfAmPm=0, NanoOfSecond=0, MicroOfSecond=0, SecondOfMinute=46},ISO resolved to 2019-04-18 of type java.time.format.Parsed
    at java.time.LocalTime.from(LocalTime.java:409)
    at java.time.LocalDateTime.from(LocalDateTime.java:457)
    ... 4 more

Answer 1

它一定要是dd-MM-yyyy HH:mm:ss

 h       clock-hour-of-am-pm (1-12)  number            12
 H       hour-of-day (0-23)          number            0

因为在您的示例中，12 可以是 AM 或 PM。

由于缺少信息，格式化程序无法决定 AM 或 PM：

 a       am-pm-of-day                text              PM

两者都有可能，因此会出现错误Unable to obtain LocalTime。