10장

1. 날짜와 시간

• Calendar 클래스: 추상 클래스이므로 메서드를 통해서 구현된 클래스의 인스턴스를 얻어야 함

• Date 클래스: Calendar 클래스가 추가되면서 대부분의 메서드가 'deprecated' 처리

  • deprecated: 더 이상 사용을 권장하지 않는 대상

2. 형식화 클래스

• 형식화 클래스: 숫자, 날짜, 텍스트 데이터 등을 일정한 형식에 맞게 표현하는 방법을 제공하는 클래스

2.1. DecimalFormat 클래스

Title	Class DecimalFormat
Module	java.base
Package	java.text
inheritance	java.lang.Object java.text.Format java.text.NumberFormat java.text.DecimalFormat
Class Description	Note	All Implemented Interfaces: Serializable, Cloneable
Type Signature	public class DecimalFormat extends NumberFormat
Block	10진수의 형식을 지정하는 NumberFormat의 구체적인 서브 클래스
Note	Since	1.1
See Also	Java Tutorial, NumberFormat DecimalFormatSymbols ParsePosition Serialized Form

2.2. 특별 패턴

Symbol	Location	Localized	Meaning
0	Number	Yes	Digit
#	Number	Yes	Digit, zero shows as absent
.	Number	Yes	Decimal separator or monetary decimal separator
-	Number	Yes	Minus sign
,	Number	Yes	Grouping separator
E	Number	Yes	Separates mantissa and exponent in scientific notation. Need not be quoted in prefix or suffix.
;	Subpattern boundary	Yes	Separates positive and negative subpatterns
%	Prefix or suffix	Yes	Multiply by 100 and show as percentage
\u2030	Prefix or suffix	Yes	Multiply by 1000 and show as per mille value
¤ (\u00A4)	Prefix or suffix	No	Currency sign, replaced by currency symbol.
'	Prefix or suffix	No	Used to quote special characters in a prefix or suffix, for example, "'#'#" formats 123 to "#123". To create a single quote itself, use two in a row: "# o''clock".

2.3. SimpleDateFormat

Title	Class SimpleDateFormat
Module	java.base
Package	java.text
inheritance	java.lang.Object java.text.Format java.text.DateFormat java.text.SimpleDateFormat
Class Description	Note	All Implemented Interfaces: Serializable, Cloneable
Type Signature	public class SimpleDateFormat extends DateFormat
Block	locale에 따라 날짜 서식을 지정하고 구문을 분석하는 DateFormat의 서브 클래스
Note	Since	1.1
See Also	Java Tutorial, Calendar, TimeZone, DateFormat, DateFormatSymbols, DateTimeFormatter, Serialized Form

2.4. 날짜와 시간 패턴

Letter	Date or Time Component	Presentation	Examples
G	Era designator	Text	AD
y	Year	Year	1996; 96
Y	Week year	Year	2009; 09
M	Month in year (context sensitive)	Month	July; Jul; 07
L	Month in year (standalone form)	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 name in week	Text	Tuesday; Tue
u	Day number of week (1 = Monday, ..., 7 = Sunday)	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

참고 자료

• 자바의 정석 - 도우출판