将时间戳解析为LocalDateTime [英] Parsing timestamp as LocalDateTime
问题描述
我想将 yyyy-MM-dd'T'HH:mm:ss
形式的时间戳解析为 LocalDateTime
。这样做时,如果秒 00
,秒将消失。
I want to parse a timestamp in the form of yyyy-MM-dd'T'HH:mm:ss
as LocalDateTime
. When doing so, it strips the seconds if they are 00
.
如此处所述,我需要使用自定义格式程序
As described here, I need to use a custom formatter
LocalDateTime date = LocalDateTime.parse("2008-10-02T12:30:00");
DateTimeFormatter f = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss");
String dateString = date.toString();
String dateFormatted = date.format(f);
System.out.println(dateString); // 2008-10-02T12:30
此方法有效,但返回 String
:
System.out.println(dateFormatted); // 2008-10-02T12:30:00
当我将字符串解析为<$ c $时c> LocalDateTime 会再次剥离 00
:
When I parse the string to LocalDateTime
it strips the 00
again:
LocalDateTime dateLDT = LocalDateTime.parse(dateFormatted, f);
System.out.println(dateLDT); // 2008-10-02T12:30
那么如何将日期解析为 LocalDateTime
,而不是 String
,并保留 00
到底?
So how can I parse a date as LocalDateTime
, instead of String
, and keep the 00
at the end?
推荐答案
您应该期望输出之间的差异
You should expect a difference in output between
LocalDateTime dateLDT = LocalDateTime.parse(dateFormatted, f);
System.out.println(dateLDT);
和
System.out.println(dateLDT.format(f)) //or f.format(dateLDT)
System.out.println(dateLDT);
打印 dateLDT.toString()
的值,
当您查看 LocalDateTime.toString()
时,不会产生与模式相同的输出。 ,您会看到它将时间部分委托给 LocalTime.toString()
,后者有条件地显示秒:
When you look at LocalDateTime.toString()
, you'll see that it delegates the time part to LocalTime.toString()
, which prints seconds conditionally:
public String toString() {
...
if (secondValue > 0 || nanoValue > 0) {
buf.append(secondValue < 10 ? ":0" : ":").append(secondValue);
...
}
}
return buf.toString();
}
如果它的值是,则仅忽略秒字段0
。
在这种情况下,您需要始终使用 DateTimeFormatter
如果必须确定输出/输入格式,则可以格式化日期。
What you need to do in this case is always use a DateTimeFormatter
to format your date if you have to be certain about the output/input format.
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