解析 LocalDateTime (Java 8) 时无法从 TemporalAccessor 获取 LocalDateTime
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/27454025/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Unable to obtain LocalDateTime from TemporalAccessor when parsing LocalDateTime (Java 8)
提问by retrography
I am simply trying to convert a date string into a DateTime object in Java 8. Upon running the following lines:
我只是想在 Java 8 中将日期字符串转换为 DateTime 对象。运行以下几行后：
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyyMMdd");
LocalDateTime dt = LocalDateTime.parse("20140218", formatter);
I get the following error:
我收到以下错误：
Exception in thread "main" java.time.format.DateTimeParseException:
Text '20140218' could not be parsed:
Unable to obtain LocalDateTime from TemporalAccessor:
{},ISO resolved to 2014-02-18 of type java.time.format.Parsed
at java.time.format.DateTimeFormatter.createError(DateTimeFormatter.java:1918)
at java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1853)
at java.time.LocalDateTime.parse(LocalDateTime.java:492)
The syntax is identical to what has been suggested here, yet I am served with an exception. I am using JDK-8u25.
语法与此处建议的相同，但我有一个例外。我正在使用JDK-8u25.
采纳答案by retrography
It turns out Java does not accept a bare Date value as DateTime. Using LocalDate instead of LocalDateTime solves the issue:
事实证明，Java 不接受一个裸 Date 值作为 DateTime。使用 LocalDate 而不是 LocalDateTime 解决了这个问题：
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyyMMdd");
LocalDate dt = LocalDate.parse("20140218", formatter);
回答by Tom B
This is a really unclear and unhelpful error message. After much trial and error I found that LocalDateTimewill give the above error if you do not attempt to parse a time. By using LocalDateinstead, it works without erroring.
这是一个非常不清楚和无用的错误消息。经过多次反复试验，我发现LocalDateTime如果您不尝试解析时间，则会出现上述错误。通过使用LocalDate，它可以正常工作而不会出错。
This is poorly documented and the related exception is very unhelpful.
这没有很好的记录，相关的异常也非常无用。
回答by ?yvind Mo
If you really need to transform a date to a LocalDateTime object, you could use the LocalDate.atStartOfDay(). This will give you a LocalDateTime object at the specified date, having the hour, minute and second fields set to 0:
如果您确实需要将日期转换为 LocalDateTime 对象，则可以使用 LocalDate.atStartOfDay()。这将在指定日期为您提供一个 LocalDateTime 对象，将小时、分钟和秒字段设置为 0：
final DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyyMMdd");
LocalDateTime time = LocalDate.parse("20140218", formatter).atStartOfDay();
回答by Iulian David
For what is worth if anyone should read again this topic(like me) the correct answer would be in DateTimeFormatterdefinition, e.g.:
如果有人应该再次阅读这个主题（像我一样），正确的答案应该是在DateTimeFormatter定义中，例如：
private static DateTimeFormatter DATE_FORMAT =
new DateTimeFormatterBuilder().appendPattern("dd/MM/yyyy[ [HH][:mm][:ss][.SSS]]")
.parseDefaulting(ChronoField.HOUR_OF_DAY, 0)
.parseDefaulting(ChronoField.MINUTE_OF_HOUR, 0)
.parseDefaulting(ChronoField.SECOND_OF_MINUTE, 0)
.toFormatter();
One should set the optional fields if they will appear. And the rest of code should be exactly the same.
如果出现可选字段，则应设置它们。其余代码应该完全相同。
回答by ZeroOne
Expanding on retrography's answer..: I had this same problem even when using LocalDateand not LocalDateTime. The issue was that I had created my DateTimeFormatterusing .withResolverStyle(ResolverStyle.STRICT);, so I had to use date pattern uuuuMMddinstead of yyyyMMdd(i.e. "year" instead of "year-of-era")!
扩展retrography的答案..：即使在使用LocalDate和不使用时，我也遇到了同样的问题LocalDateTime。问题是我创建了DateTimeFormatterusing .withResolverStyle(ResolverStyle.STRICT);，所以我必须使用日期模式uuuuMMdd而不是yyyyMMdd（即“年份”而不是“年代”）！
DateTimeFormatter formatter = new DateTimeFormatterBuilder()
.parseStrict()
.appendPattern("uuuuMMdd")
.toFormatter()
.withResolverStyle(ResolverStyle.STRICT);
LocalDate dt = LocalDate.parse("20140218", formatter);
(This solution was originally a comment to retrography's answer, but I was encouraged to post it as a stand-alone answer because it apparently works really well for many people.)
（这个解决方案最初是对逆转录的答案的评论，但我被鼓励将其作为独立的答案发布，因为它显然对许多人来说非常有效。）
回答by prime
If the date String does not include any value for hours, minutes and etc you cannot directly convert this to a LocalDateTime. You can only convert it to a LocalDate, because the string onlyrepresentthe year,month and datecomponents it would be the correct thing to do.
如果日期字符串不包含小时、分钟等的任何值，则不能直接将其转换为LocalDateTime. 您只能将其转换为一个LocalDate，因为字符串仅代表了年份，月份和日期组件它是做正确的事。
DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyyMMdd");
LocalDate ld = LocalDate.parse("20180306", dtf); // 2018-03-06
Anyway you can convert this to LocalDateTime.
无论如何，您可以将其转换为LocalDateTime.
DateTimeFormatter dtf = DateTimeFormatter.ofPattern("yyyyMMdd");
LocalDate ld = LocalDate.parse("20180306", dtf);
LocalDateTime ldt = LocalDateTime.of(ld, LocalTime.of(0,0)); // 2018-03-06T00:00
回答by mawburn
For anyone who landed here with this error, like I did:
对于遇到此错误的任何人，就像我一样：
Unable to obtain LocalDateTime from TemporalAccessor: {HourOfAmPm=0, MinuteOfHour=0}
Unable to obtain LocalDateTime from TemporalAccessor: {HourOfAmPm=0, MinuteOfHour=0}
It came from a the following line:
它来自以下行：
LocalDateTime.parse(date, DateTimeFormatter.ofPattern("M/d/yy h:mm"));
It turned out that it was because I was using a 12hr Hour pattern on a 0 hour, instead of a 24hr pattern.
原来这是因为我在 0 小时使用了 12 小时模式，而不是 24 小时模式。
Changing the hour to 24hr pattern by using a capital H fixes it:
使用大写 H 将小时更改为 24 小时模式修复它：
LocalDateTime.parse(date, DateTimeFormatter.ofPattern("M/d/yy H:mm"));
回答by Vinay Kasarla
Try this one:
试试这个：
DateTimeFormatter dateTimeFormatter = DateTimeFormatter.ofPattern("MM-dd-yyyy");
LocalDate fromLocalDate = LocalDate.parse(fromdstrong textate, dateTimeFormatter);
You can add any format you want. That works for me!
您可以添加任何您想要的格式。这对我行得通！
回答by Jeff Cook
This works fine
这工作正常
public class DateDemo {
public static void main(String[] args) {
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("dd-MM-yyyy hh:mm");
String date = "16-08-2018 12:10";
LocalDate localDate = LocalDate.parse(date, formatter);
System.out.println("VALUE="+localDate);
DateTimeFormatter formatter1 = DateTimeFormatter.ofPattern("dd-MM-yyyy HH:mm");
LocalDateTime parse = LocalDateTime.parse(date, formatter1);
System.out.println("VALUE1="+parse);
}
}
output:
输出：
VALUE=2018-08-16
VALUE1=2018-08-16T12:10
