Introduction to Date and Time API

Introduction to Date and Time API HASUNUMA Kenji Vice
president, GlassFish Users Group Japan k.hasunuma@coppermine.jp Twitter: @btnrouge November 10, 2012

Javaʹ͓͚Δ೔෇ɾ࣌ࠁͷѻ͍ JDK 1.1 Ҏ߱ɺຊ࣭తʹ͸มԽͳ͠

java.util.Date (JDK 1.0) wANSI/ISO Cͱػೳతʹಉ౳ wUTCPSϩʔΧϧλΠϜκʔϯ w೥݄೔࣌෼ඵΛऔಘɾઃఆՄ w೔෇ͱ࣌ࠁΛಉ͡ΫϥεͰද͢

java.util.Date (JDK 1.1) wࠃࡍԽରԠʜ࣮૷ΛCalendarϕʔεʹஔ ͖׵͑ w೥݄೔࣌෼ඵΛૢ࡞͢Δϝιου ͸͢΂ͯඇਪ঑ˠCalendarͰ୅ସ w೔෇ૢ࡞͸CalendarʹҠߦɺ%BUF͸೔ ࣌Λࢦ͚ࣔͩ͢͠

java.util.Dateͷ՝୊ wϑΟʔϧυૢ࡞͕໘౗ w ೥ϑΟʔϧυ ͕࣮ࡍͷ೥ w ݄͕0͔Β࢝·Δ ݄ˠɺ݄ˠ w೔෇෦ͱ࣌ࠁ෦͕ࠞࡏ͍ͯ͠Δ
w೔෇ԋࢉͱϑΥʔϚοτػೳ͕ශऑ

JSR 310 Date and Time API

Michael Nascimento Santos Stephen Colebourne Roger Riggs

JSR 310 : Date and Time API wDateɺCalendarɺDateFormat౳Λஔ͖ ׵͑Δ͜ͱ͕໨త wISO
8601ܗࣜͷ೔෇ɾ࣌ࠁදݱ wImmutable͔ͭεϨουηʔϑͳAPI wઃܭࢥ૝͸Joda-Timeʹࠅࣅ

Joda-Time JSR 310

Second System Syndrome

More simply

JSR 310 : Date and Time API 2007೥2݄JSR 310ঝೝɺEGൃ଍ 2008೥5݄JavaOne
2008Ͱൃද 2010೥3݄Early Draft Review (1ճ໨) 2012೥10݄Early Draft Review (2ճ໨) 2013೥10݄ Java SE 8ϦϦʔε

java.util.Date JSR 310 ΦϒδΣΫτ Mutable Immutable ਫ਼౓ ϛϦඵ φϊඵ ϑΟʔϧυR/W
Calendarܦ༝ ௚઀αϙʔτ λΠϜκʔϯ αϙʔτ αϙʔτ toString໭Γ஋ Unixܗࣜ ISO 8601ܗࣜ ೔෇ͱ࣌ࠁͷ෼཭ ෆՄ Մೳ ೔෇ԋࢉ ൺֱͷΈ ༷ʑͳ೔෇ԋࢉ ؔ࿈Ϋϥε਺ ਺ݸ ͨ͘͞Μ

ϝϦοτ w݄1ʙ12 Date, Calendar͸0ʙ11 wtoStringͰISO 8601ܗࣜΛฦ͢ w೔෇ͱ࣌ࠁΛ෼཭͢Δ͜ͱ͕Ͱ͖Δ wଟ༷ͳ೔෇ԋࢉػೳΛ࣋ͭ wεϨουηʔϑͰ͋Δ

σϝϦοτ w αΠζ͕େ͖͍ Ϋϥε਺͕ଟ͍   ˠJava SE APIͷதͰ΋࠷େڃ w طଘAPIͱͷޓ׵ੑʹ๡͍͠
w ࠓޙͷల։ JPA΍JAXB΁ͷରԠ ͕ෆ໌ྎ w Early Draft Reviewޙ΋සൟͳ࢓༷มߋ

ࢀߟ: ISO 8601ܗࣜ w ೔෇yyyy-MM-dd • 2012-11-10 w ࣌ࠁhh:mm:ss.SSSZ •
07:30:00.000Z w ೔࣌yyyy-MM-dd’T’HH:mm:ss.SSSZ • 2012-11-10T07:30:00.000Z

JSR 310 Essentials

Ϛγϯ޲͚ͷදݱ ಺෦දݱ • Instant • Duration • Clock ਓؒ޲͚ͷදݱ
֎෦දݱ • DateTime • Period • Chronology

Instant

Duration

DateTime : ೔෇ɾ࣌ࠁΫϥε • DateTimeΠϯλϑΣʔεͷ࣮૷ • ݱࡏ೔࣌·ͨ͸೚ҙͷ೔͔࣌Βੜ੒ • DateTimeͷԋࢉ(plus/minus)͓Αͼଞͷ DateTime͔Βͷม׵Λαϙʔτ
• InstantʹରԠ͢Δਓؒ޲͚දݱ

DateTimeΠϯλϑΣʔεͷ࣮૷ • LocalDate, LocalTime, LocalDateTime • OffsetDate, OffsetTime, OffsetDateTime •
ZonedDateTime • ෆ଍৘ใͷ௥Ճ·ͨ͸༨৒৘ใͷ੾Γࣺ ͯʹΑΓ૬ޓʹม׵Մ

%BUF 5JNF %BUF5JNF -PDBM ೥݄೔ ! ࣌ࠩ৘ใͳ͠ ! ࣌෼ඵະຬ ࣌ࠩ৘ใͳ͠
೥݄೔ ࣌෼ඵະຬ ࣌ࠩ৘ใͳ͠ 0⒎TFU ೥݄೔ ! 65$͔Βͷ࣌ࠩ ! ࣌෼ඵະຬ 65$͔Βͷ࣌ࠩ ೥݄೔ ࣌෼ඵະຬ 65$͔Βͷ࣌ࠩ ;POFE /" /" ೥݄೔ ࣌෼ඵະຬ λΠϜκʔϯ

OﬀsetDateTime vs. ZonedDateTime wOﬀsetDateTimeUTC͔Βͷ࣌ࠩ wZonedDateTime࣮ࡍͷλΠϜκʔϯ ˞λΠϜκʔϯʹΑͬͯ͸͕࣌ࠩมಈ͢Δ wՆ࣌ؒಋೖࠃͰ͸ຖ೥ൃੜ wλΠϜκʔϯͷ࣌ࠩͷมߋ

Period : ظؒΫϥε wظؒΛද͢ ྫϲ݄ͱ೔ͱ࣌ؒ wϑΟʔϧυ௚઀ࢦఆɺͭͷDateTimeɺ Duration͔Βੜ੒ wϑΟʔϧυऔಘɺPeriodͷplus/minusɺ Duration΁ͷม׵ͳͲΛαϙʔτ
wDurationʹରԠ͢Δਓؒ޲͚දݱ

Chronology : ྐྵΫϥε • ChronologyΫϥε:  ྐྵͷ৘ใΛอ࣋ɺChronoDateΛੜ੒ • ChronoDateΫϥε:  DateTimeΛϥοϓ֤ͯ͠ʑͷྐྵʹม׵  ˞࠷৽ͷ࣮૷Ͱ͸ෳ਺Ϋϥεʹ෼ׂ
ChronoLocalDateɺChronoOﬀsetDateTime౳

ChronologyͷαϒΫϥε • ISOChronology - ISO 8601 ඪ४ • JapaneseChronology࿨ྐྵ
೔ຊ • ThaiBuddhistChronology෹ྐྵ λΠ • MinguoChronologyຽࠃلݩ ୆࿷ • HijrahChronologyΠεϥϜྐྵ

೔෇ɾ࣌ࠁԋࢉ wDateTimeɺPeriodɺInstantɺDuration͸ ͦΕࣗ਎͕ՃࢉɾݮࢉػೳΛ࣋ͭ wϑΟʔϧυΛද͢Ϋϥεɾྻڍܕ͕֤छ ԋࢉΛఏڙ w Yearˠ͏Δ͏೥൑ఆ w Monthˠ݄ͷ೔਺औಘ w
DayOfWeekˠ༵೔औಘ

ϑΥʔϚοτػೳ wDateTimeFormatter:  ग़ྗܗࣜΛΧελϚΠζ͢Δ wDateTimeFormatterBuilder͔Βൺֱత؆ ୯ʹDateTimeFormatterΛੜ੒Մೳ wjava.text.DateFormat͸JSR 310Ͱ͸࢖༻ Ͱ͖ͳ͍

Examples

ࠓ೔ͷ೔෇ΛऔಘˠEBUF LocalDate date = LocalDate.now();

೥݄೔ˠEBUF LocalDate date =   LocalDate.of(2012, 11, 10);

ࠓ೔ͷ೔෇ˠE ೔ޙͷ೔෇ˠE LocalDate d1 = LocalDate.now(); LocalDate d2 = d1.plusDays(3);

ࠓ೔ͷ೔෇ˠEBUF ࠓ೔ͷ࣌෼ˠEBUF5JNF LocalDate date = LocalDate.now(); LocalDateTime dateTime =  
date.atTime(16, 30);

ࠓ೔ͷ೔࣌ˠEBUF5JNF ࠓ೔ͷ೔෇ˠEBUF LocalDateTime dateTime =   LocalDateTime.now(); LocalDate date = 
LocalDate.from(dateTime);

EBUF೥݄೔ ͏Δ͏೥ ˠMFBQUSVF LocalDate date = LocalDate.of(1992, 10, 8);
boolean leap = Year.from(date).isLeap();

ࠓ೔ͷ೔෇ˠEBUF EBUFΛඪ४ग़ྗ΁ LocalDate date = LocalDate.now(); System.out.println(date.toString()); 2012-11-10 ग़ྗ݁Ռ

ࠓ೔ͷ೔෇ ࿨ྐྵ ˠEBUF JapaneseChronology chrono = JapaneseChronology.INSTANCE; ChronoLocalDate<JapaneseChronology> jdate =
chrono.date(LocalDate.now()); System.out.println(jdate); H24-11-10 ग़ྗ݁Ռ

Compatibility

java.util.DateΛվम(OpenJDK8) wίϯετϥΫλDate(Instant instant)  㱻ίϯετϥΫλDate(long date) wInstant toInstant()ϝιου  㱻long getTime()ϝιου ˞java.util.Calendarʹ΋ಉ༷ͷվम

0⒎TFU%BUF5JNF͔Β*OTUBOUΛऔಘ औಘͨ͠*OTUBOU͔Β%BUFΛੜ੒ OffsetDateTime dateTime =  OffsetDateTime.now(); Instant instant =  
dateTime.toInstant(); Date date = new Date(instant);

ଞͷAPIͱͷ࿈ܞ wকདྷతʹ͸JPAɺJAXB౳΁ల։༧ఆ wͨͩ͠ݱ࣌఺Ͱ͸۩ମతΞΫγϣϯͳ͠ wJPA࿈ܞ͸ૣظ࣮ݱΛ໨ࢦͯ͠ܭըதɺ ͱͷ͜ͱ ͍ͭʹͳΔ͜ͱ΍Βʜ

Conclusion

JSR 310ͱ͸Կͳͷ͔ wJSR 310͸java.util.Dateͷܽ఺Λ͢΂ͯ ղܾ͠Α͏ͱ͢Δ໺৺తࢼΈ wաڈͱͷޓ׵ੑΛஅͪ੾Δ͜ͱͰɺ೔ ෇ɾ࣌ࠁAPIͷཧ૝Λ௥ٻͨ͠ wਖ਼௚΍Γա͗ײ΋൱Ίͳ͍͕ɺطଘAPI ͷ໰୊఺ͷଟ͘Λղܾͨ͠఺͸ධՁ

JSR 310ͷϦιʔε JSR 310 Speciﬁcation http://jcp.org/en/jsr/detail?id=310 JSR 310 RI “ThreeTen”
http://threeten.sourceforge.net https://github.com/ThreeTen/threeten

Introduction to Date and Time API HASUNUMA Kenji k.hasunuma@coppermine.jp Twitter:
@btnrouge

Introduction to Date and Time API

Introduction to Date and Time API

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