java獲取系統時間的一個小陷阱

	long time = System.currentTimeMillis();
	Date date = new Date(time);
	SimpleDateFormat sdf12 = new SimpleDateFormat("yyyyMMdd-HHmmss");
	System.out.println(sdf12.format(date));
	SimpleDateFormat sdf23 = new SimpleDateFormat("yyyyMMdd-hhmmss");
	System.out.println(sdf23.format(date));

兩個print的輸出結果是

20120813-142051
20120813-022051

可以發現，HH表示0-23小時制，hh表示0-12小時制，

附錄，轉自java docs

Date and Time Patterns

Letter	Date or Time Component	Presentation	Examples
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
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