Android SimpleDateFormat，如何使用它？

android java

2022-08-31 20:41:20

我正在尝试像这样使用Android：SimpleDateFormat

String _Date = "2010-09-29 08:45:22"
SimpleDateFormat fmt = new SimpleDateFormat("yyyy-MM-dd");

try {
    Date date = fmt.parse(_Date);
    return fmt.format(date);
}
catch(ParseException pe) {
    return "Date";    
}

结果是好的，我有： 2010-09-29

但是，如果我将SimpleDateFormat

SimpleDateFormat("dd-MM-yyyy");

问题是我会得到03-03-0035!!!!

为什么以及如何获得这样的格式？dd-MM-yyyy

答案 1

我假设你想反转日期格式？

SimpleDateFormat可用于解析和格式化。您只需要两种格式，一种用于解析字符串，另一种用于返回所需的打印输出：

SimpleDateFormat fmt = new SimpleDateFormat("yyyy-MM-dd");
Date date = fmt.parse(dateString);

SimpleDateFormat fmtOut = new SimpleDateFormat("dd-MM-yyyy");
return fmtOut.format(date);

从Java 8开始：

DateTimeFormatter fmt = DateTimeFormatter.ofPattern("yyyy-MM-dd").withZone(ZoneOffset.UTC);
TemporalAccessor date = fmt.parse(dateString);
Instant time = Instant.from(date);

DateTimeFormatter fmtOut = DateTimeFormatter.ofPattern("dd-MM-yyyy").withZone(ZoneOffset.UTC);
return fmtOut.format(time);

答案 2

以下是所有可用的日期格式，请在此处阅读更多文档。

Symbol  Meaning                Kind         Example
D       day in year             Number        189
E       day of week             Text          E/EE/EEE:Tue, EEEE:Tuesday, EEEEE:T
F       day of week in month    Number        2 (2nd Wed in July)
G       era designator          Text          AD
H       hour in day (0-23)      Number        0
K       hour in am/pm (0-11)    Number        0
L       stand-alone month       Text          L:1 LL:01 LLL:Jan LLLL:January LLLLL:J
M       month in year           Text          M:1 MM:01 MMM:Jan MMMM:January MMMMM:J
S       fractional seconds      Number        978
W       week in month           Number        2
Z       time zone (RFC 822)     Time Zone     Z/ZZ/ZZZ:-0800 ZZZZ:GMT-08:00 ZZZZZ:-08:00
a       am/pm marker            Text          PM
c       stand-alone day of week Text          c/cc/ccc:Tue, cccc:Tuesday, ccccc:T
d       day in month            Number        10
h       hour in am/pm (1-12)    Number        12
k       hour in day (1-24)      Number        24
m       minute in hour          Number        30
s       second in minute        Number        55
w       week in year            Number        27
G       era designator          Text          AD
y       year                    Number        yy:10 y/yyy/yyyy:2010
z       time zone               Time Zone     z/zz/zzz:PST zzzz:Pacific Standard