Java 非ISO日历系统
2018-03-12 14:57 更新
Java日期时间 - Java非ISO日历系统
LocalDate使用ISO日历系统,这是公历。
Java Date-Time API还支持其他日历,例如泰国佛教日历,Hijrah日历,Minguo日历和日历。
非ISO日历相关类在java.time.chrono包中定义。
对于每个可用的非ISO日历系统,有一个自定义的年表和自定义的Date类。
自定义的Chronology类表示日历系统,而自定义的Date类表示自定义日历系统中的日期。
每个自定义Chronology类都包含一个INSTANCE常量,表示该类的单例实例。
例子
以下代码显示获取泰国佛教日历中的当前日期:
import java.time.chrono.ThaiBuddhistChronology; import java.time.chrono.ThaiBuddhistDate; public class Main { public static void main(String[] args) { ThaiBuddhistChronology thaiBuddhistChrono = ThaiBuddhistChronology.INSTANCE; ThaiBuddhistDate now = thaiBuddhistChrono.dateNow(); ThaiBuddhistDate now2 = ThaiBuddhistDate.now(); System.out.println("Current Date in Thai Buddhist: " + now); System.out.println("Current Date in Thai Buddhist: " + now2); } }
上面的代码生成以下结果。
![](https://atts.w3cschool.cn/attachments/jimg/java_date_time/EXAMPLE__E56B14507C2D00775876.png)
例2
我们可以使用 from()
方法将日历系统中的日期转换为另一个日历系统。
以下代码显示如何将ISO日期转换为泰语佛教日期,反之亦然。
import java.time.LocalDate; import java.time.chrono.ThaiBuddhistDate; public class Main { public static void main(String[] args) { ThaiBuddhistDate thaiBuddhistNow = ThaiBuddhistDate.now(); LocalDate isoNow = LocalDate.now(); System.out.println("Thai Buddhist Current Date: " + thaiBuddhistNow); System.out.println("ISO Current Date: " + isoNow); // Convert Thai Buddhist date to ISO date and vice versa ThaiBuddhistDate thaiBuddhistNow2 = ThaiBuddhistDate.from(isoNow); LocalDate isoNow2 = LocalDate.from(thaiBuddhistNow); System.out.println("Thai Buddhist Current Date from ISO: " + thaiBuddhistNow2); System.out.println("ISO Current Date from Thai Buddhist: " + isoNow2); } }
上面的代码生成以下结果。
![](https://atts.w3cschool.cn/attachments/jimg/java_date_time/EXAMPLE_2__AE3FB9B6B8ED3019A1B6.png)
例3
以下代码显示如何将日期转换为不同的日期系统。
/* * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * - Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * - Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * - Neither the name of Oracle or the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ import java.time.*; import java.time.chrono.*; import java.time.format.*; import java.time.temporal.*; import java.util.Locale; import java.io.PrintStream; /* * Convert LocalDate -> ChronoLocalDate -> String and back. */ public class Main { /** * Converts a LocalDate (ISO) value to a ChronoLocalDate date using the * provided Chronology, and then formats the ChronoLocalDate to a String using * a DateTimeFormatter with a SHORT pattern based on the Chronology and the * current Locale. * * @param localDate * - the ISO date to convert and format. * @param chrono * - an optional Chronology. If null, then IsoChronology is used. */ public static String toString(LocalDate localDate, Chronology chrono) { if (localDate != null) { Locale locale = Locale.getDefault(Locale.Category.FORMAT); ChronoLocalDate cDate; if (chrono == null) { chrono = IsoChronology.INSTANCE; } try { cDate = chrono.date(localDate); } catch (DateTimeException ex) { System.err.println(ex); chrono = IsoChronology.INSTANCE; cDate = localDate; } String pattern = "M/d/yyyy GGGGG"; DateTimeFormatter dateFormatter = DateTimeFormatter.ofPattern(pattern); return dateFormatter.format(cDate); } else { return ""; } } /** * Parses a String to a ChronoLocalDate using a DateTimeFormatter with a short * pattern based on the current Locale and the provided Chronology, then * converts this to a LocalDate (ISO) value. * * @param text * - the input date text in the SHORT format expected for the * Chronology and the current Locale. * * @param chrono * - an optional Chronology. If null, then IsoChronology is used. */ public static LocalDate fromString(String text, Chronology chrono) { if (text != null && !text.isEmpty()) { Locale locale = Locale.getDefault(Locale.Category.FORMAT); if (chrono == null) { chrono = IsoChronology.INSTANCE; } String pattern = "M/d/yyyy GGGGG"; DateTimeFormatter df = new DateTimeFormatterBuilder().parseLenient() .appendPattern(pattern).toFormatter().withChronology(chrono) .withDecimalStyle(DecimalStyle.of(locale)); TemporalAccessor temporal = df.parse(text); ChronoLocalDate cDate = chrono.date(temporal); return LocalDate.from(cDate); } return null; } public static void main(String[] args) { LocalDate date = LocalDate.of(1996, Month.OCTOBER, 29); System.out.printf("%s%n", toString(date, JapaneseChronology.INSTANCE)); System.out.printf("%s%n", toString(date, MinguoChronology.INSTANCE)); System.out.printf("%s%n", toString(date, ThaiBuddhistChronology.INSTANCE)); System.out.printf("%s%n", toString(date, HijrahChronology.INSTANCE)); System.out.printf("%s%n", fromString("10/29/0008 H", JapaneseChronology.INSTANCE)); System.out.printf("%s%n", fromString("10/29/0085 1", MinguoChronology.INSTANCE)); System.out.printf("%s%n", fromString("10/29/2539 B.E.", ThaiBuddhistChronology.INSTANCE)); System.out.printf("%s%n", fromString("6/16/1417 1", HijrahChronology.INSTANCE)); } }
上面的代码生成以下结果。
![](https://atts.w3cschool.cn/attachments/jimg/java_date_time/EXAMPLE_3__25B4A28FC7259E0DB7F1.png)
以上内容是否对您有帮助:
更多建议: