使用DateTimeFormatter解析AM/PM时间时的Java 8 DateTimeParseException

Question

import java.time.LocalTime;
import java.time.format.DateTimeFormatter;

public class FormatterExample {
    private static final DateTimeFormatter timeFormatter = DateTimeFormatter.ofPattern("HH:mm a");
    public static void main(String[] args) {
        parseDateAndPrint("08:06 AM");
        parseDateAndPrint("08:06 PM");
    }
    public static void parseDateAndPrint(String time) {
        LocalTime localTime = LocalTime.parse((time), timeFormatter);
        System.out.println(localTime.format(timeFormatter));
    }
}

08:06 AM
Exception in thread "main" java.time.format.DateTimeParseException: Text '08:06 PM' could not be parsed: Conflict found: Field AmPmOfDay 0 differs from AmPmOfDay 1 derived from 08:06
    at java.time.format.DateTimeFormatter.createError(DateTimeFormatter.java:1919)
    at java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1854)
    at java.time.LocalTime.parse(LocalTime.java:441)
    at FormatterExample.parseDateAndPrint(FormatterExample.java:11)
    at FormatterExample.main(FormatterExample.java:8)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:483)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:134)
Caused by: java.time.DateTimeException: Conflict found: Field AmPmOfDay 0 differs from AmPmOfDay 1 derived from 08:06
    at java.time.format.Parsed.crossCheck(Parsed.java:582)
    at java.time.format.Parsed.crossCheck(Parsed.java:563)
    at java.time.format.Parsed.resolve(Parsed.java:247)
    at java.time.format.DateTimeFormatter.parseResolved0(DateTimeFormatter.java:1954)
    at java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1850)
    ... 8 more

Text '08:06 PM' could not be parsed: Conflict found: Field AmPmOfDay 0 differs from AmPmOfDay 1 derived from 08:06

但这就是我卡住的地方..我不确定这个错误到底是什么意思，但它肯定与输入字符串的AM/PM部分有关。我也尝试搜索类似的错误，但我没有找到任何东西。我有一种感觉，我可能在定义格式化程序模式时犯了一个简单的错误，但我卡住了。任何帮助都将不胜感激！

Answer 1

您使用了错误的模式，h是hour-of day（0-23）；您需要h。

错误是告诉您h是24小时，而8显然是AM。因此，当您告诉解析器在24小时内使用8并告诉解析器它是PM时，它就会爆炸。

简而言之，阅读文档。