Question

我的日期格式为＆＃34; 12-JAN-15 03.51.22.638000000 AM＆＃34;。我希望它转换为＆＃34; 12-01-15 00：00：00.000＆＃34; 即使有小时，小时和秒等，我只想输出零。

Answer 1

您想要将一种日期格式转换为另一种日期格式。 This answer正是如此。它声明

DateFormat originalFormat = new SimpleDateFormat("MMMM dd, yyyy", Locale.ENGLISH);
DateFormat targetFormat = new SimpleDateFormat("yyyyMMdd");
Date date = originalFormat.parse("August 21, 2012");
String formattedDate = targetFormat.format(date);  // 20120821

在您的情况下，原始格式和目标格式如下

原始格式：dd-MMM-yy hh.mm.ss.N a 目标格式：dd-MM-yy hh:mm:ss:S

我不知道如何用0替换时间数据。也许字符串操作是你的情况。但是如果你想要更多控制，那么你可以做这样的事情。

Calendar cal = Calendar.getInstance();
cal.setTime(date); // this is the date we parsed above
cal.set(Calendar.HOUR_OF_DAY,0);
cal.set(Calendar.MINUTE,0);
cal.set(Calendar.SECOND,0);
cal.set(Calendar.MILLISECOND,0);
formattedDate = targetFormat.format(cal.getTime());

修改 @ Sufiyan Ghori提供了一种更清洁的方式。

Answer 2

使用Java 8，

DateTimeFormatter formatter = DateTimeFormatter
            .ofPattern("MM-dd-yy:hh:mm:ss:nn"); // n = nano-of-second

LocalDateTime today = LocalDateTime.of(LocalDate.of(2015, 1, 15),
            LocalTime.of(00, 00, 00, 00));

System.out.println(today.format(formatter));

<强> 输出

01-15-15:12:00:00:00

<强>解释

LocalDateTime.of(LocalDate.of(int Year, int Month, int Day), 
                LocalTime.of(int Hour, int Minutes, int Seconds, int nanoOfSeconds));

Answer 3

        String dateInString = "12-JAN-15 10.17.07.107000000 AM";
        dateInString = dateInString.substring(0, 9);
        Date date = null;
        try {
            date = new SimpleDateFormat("dd-MMM-yy", Locale.ENGLISH).parse(dateInString);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        String newFormat = new SimpleDateFormat("dd-MM-yy 00:00:00.000").format(date);
        System.out.println(newFormat);

Answer 4

String string = "January 2, 2010";
DateFormat format = new SimpleDateFormat("MMMM d, yyyy", Locale.ENGLISH);
Date date = format.parse(string);
System.out.println(date); // Sat Jan 02 00:00:00 GMT 2010

您可以按照此javadoc进行操作，列出所有可用的格式模式：

G   Era designator       Text               AD
y   Year                 Year               1996; 96
M   Month in year        Month              July; Jul; 07
w   Week in year         Number             27
W   Week in month        Number             2
D   Day in year          Number             189
d   Day in month         Number             10
F   Day of week in month Number             2
E   Day in week          Text               Tuesday; Tue
u   Day number of week   Number             1
a   Am/pm marker         Text               PM
H   Hour in day (0-23)   Number             0
k   Hour in day (1-24)   Number             24
K   Hour in am/pm (0-11) Number             0
h   Hour in am/pm (1-12) Number             12
m   Minute in hour       Number             30
s   Second in minute     Number             55
S   Millisecond          Number             978
z   Time zone            General time zone  Pacific Standard Time; PST; GMT-     08:00
Z   Time zone            RFC 822 time zone  -0800
X   Time zone            ISO 8601 time zone -08; -0800; -08:00

您可以参考此answer获取详细说明。

如何转换＆＃34; 12-JAN-15 03.51.22.638000000 AM＆＃34;在java？

4 个答案:

使用Java 8，