使用Java从Date中识别季节
我从来没有什么好运，所以为什么不再试一次？
我有一个应用程序，需要根据一年中的季节（春季，夏季，冬季，秋季）显示不同的图像。 这些季节我有非常具体的开始和结束日期。
我想要的天才是一个名为GetSeason的方法，它以日期作为输入并返回Spring，Summer，Winter或Fall的String值。 以下是日期范围及其相关季节：
弹簧：3 / 1-4 / 30
夏季：5 / 1-8 / 31
掉落：9/1〜10/31
冬季：11 / 1-2 / 28
有人能提供一种工作方法来恢复正常的季节吗？ 感谢大家！
似乎只是检查月份会做：
private static final String seasons[] = { "Winter", "Winter", "Spring", "Spring", "Spring", "Summer", "Summer", "Summer", "Fall", "Fall", "Fall", "Winter" }; public String getSeason( Date date ) { return seasons[ date.getMonth() ]; } // As stated above, getMonth() is deprecated, but if you start with a Date, // you'd have to convert to Calendar before continuing with new Java, // and that's not fast. 这里有一些好的答案，但它们已经过时了。 java.time类使这项工作更容易。
java.time
与最早版本的Java捆绑在一起的麻烦的旧类已被Java 8及更高版本中内置的java.time类所取代。 请参阅Oracle教程 。 许多function已经在ThreeTen-Backport中移植到Java 6和7中，并在ThreeTenABP中进一步适应Android。
Month
鉴于这里使用整月来定义季节，我们可以使用方便的Month 枚举 。 这样的枚举值优于纯整数值（1-12），因为它们是类型安全的并且保证有效值。
EnumSet
EnumSet是一种快速执行且紧凑的内存方式，用于跟踪枚举值的子集。
EnumSet spring = EnumSet.of( Month.MARCH , Month.APRIL ); EnumSet summer = EnumSet.of( Month.MAY , Month.JUNE , Month.JULY , Month.AUGUST ); EnumSet fall = EnumSet.of( Month.SEPTEMBER , Month.OCTOBER ); EnumSet winter = EnumSet.of( Month.NOVEMBER , Month.DECEMBER , Month.JANUARY , Month.FEBRUARY );
例如，我们获取特定时区的当前时刻。
ZoneId zoneId = ZoneId.of( "America/Montreal" ); ZonedDateTime zdt = ZonedDateTime.now( zoneId );
询问其Month日期时间值。
Month month = Month.from( zdt );
通过调用contains查找EnumSet具有该特定月值的季节。
if ( spring.contains( month ) ) { … } else if ( summer.contains( month ) ) { … } else if ( fall.contains( month ) ) { … } else if ( winter.contains( month ) ) { … } else { // FIXME: Handle reaching impossible point as error condition. }
定义自己的“季节”枚举
如果您在代码库中使用本季创意，我建议您定义自己的枚举“Season”。
基本的枚举很简单： public enum Season { SPRING, SUMMER, FALL, WINTER; } public enum Season { SPRING, SUMMER, FALL, WINTER; } 。 但我们还添加了一种静态方法来查找哪个月映射到哪个季节。
package com.example.javatimestuff; import java.time.Month; public enum Season { SPRING, SUMMER, FALL, WINTER; static public Season of ( Month month ) { switch ( month ) { // Spring. case MARCH: // Java quirk: An enum switch case label must be the unqualified name of an enum. So cannot use `Month.MARCH` here, only `MARCH`. return Season.SPRING; case APRIL: return Season.SPRING; // Summer. case MAY: return Season.SUMMER; case JUNE: return Season.SUMMER; case JULY: return Season.SUMMER; case AUGUST: return Season.SUMMER; // Fall. case SEPTEMBER: return Season.FALL; case OCTOBER: return Season.FALL; // Winter. case NOVEMBER: return Season.WINTER; case DECEMBER: return Season.WINTER; case JANUARY: return Season.WINTER; case FEBRUARY: return Season.WINTER; default: System.out.println ( "ERROR." ); // FIXME: Handle reaching impossible point as error condition. return null; } } }
以下是如何使用该枚举。
ZoneId zoneId = ZoneId.of ( "America/Montreal" ); ZonedDateTime zdt = ZonedDateTime.now ( zoneId ); Month month = Month.from ( zdt ); Season season = Season.of ( month );
转储到控制台。
System.out.println ( "zdt: " + zdt + " | month: " + month + " | season: " + season );
zdt：2016-06-25T18：23：14.695-04：00 [美国/蒙特利尔] | 月：6月| 季节：夏天
我感到光顾，但受宠若惊。 所以我会这样做。
这不仅会检查月份，还会检查月份。
import java.util.* public String getSeason(Date today, int year){ // the months are one less because GC is 0-based for the months, but not days. // ie 0 = January. String returnMe = ""; GregorianCalender dateToday = new GregorianCalender(year, today.get(Calender.MONTH_OF_YEAR), today.get(Calender.DAY_OF_MONTH); GregorianCalender springstart = new GregorianCalender(year, 2, 1); GregorianCalender springend = new GregorianCalender(year, 3, 30); GregorianCalender summerstart = new GregorianCalender(year, 4, 1); GregorianCalender summerend = new GregorianCalender(year, 7, 31); GregorianCalender fallstart = new GregorianCalender(year, 8, 1); GregorianCalender fallend = new GregorianCalender(year, 9, 31); GregorianCalender winterstart = new GregorianCalender(year, 10, 1); GregorianCalender winterend = new GregorianCalender(year, 1, 28); if ((dateToday.after(springstart) && dateToday.before(springend)) || dateToday.equals(springstart) || dateToday.equals(springend)){ returnMe = "Spring"; else if ((dateToday.after(summerstart) && dateToday.before(summerend)) || dateToday.equals(summerstart) || dateToday.equals(summerend)){ returnMe = "Summer"; else if ((dateToday.after(fallstart) && dateToday.before(fallend)) || dateToday.equals(fallstart) || dateToday.equals(fallend)){ returnMe = "Fall"; else if ((dateToday.after(winterstart) && dateToday.before(winterend)) || dateToday.equals(winterstart) || dateToday.equals(winterend)){ returnMe = "Winter"; else { returnMe = "Invalid"; } return returnMe; }
我确信这很可怕，可以改进。 请在评论中告诉我。
好吧，它可以很简单
String getSeason(int month) { switch(month) { case 11: case 12: case 1: case 2: return "winter"; case 3: case 4: return "spring"; case 5: case 6: case 7: case 8: return "summer"; default: return "autumn"; } }
我在评论中被谴责为一个更好的解决方案：枚举：
public static Enum Season { WINTER(Arrays.asList(11,12,1,2)), SPRING(Arrays.asList(3,4)), SUMMER(Arrays.asList(5,6,7,8)), AUTUMN(Arrays.asList(9,10)); Season(List months) { this.monthlist = months; } private List monthlist; public boolean inSeason(int month) { return this.monthlist.contains(month); // if months are 0 based, then insert +1 before the ) } public static Season seasonForMonth(int month) { for(Season s: Season.values()) { if (s.inSeason(month)) return s; } throw new IllegalArgumentException("Unknown month"); } }
import java.util.Scanner; public class lab6project1 { public static void main(String[] args) { Scanner keyboard = new Scanner(System.in); System.out.println("This program reports the season for a given day and month"); System.out.println("Please enter the month and day as integers with a space between the month and day"); int month = keyboard.nextInt(); int day = keyboard.nextInt(); if ( (month == 1) || (month == 2)) System.out.println("The season is Winter"); else if ( (month == 4) || (month == 5)) System.out.println("The season is Spring"); else if ( (month == 7) || (month == 8)) System.out.println("The season is Summer"); else if ( (month == 10)|| (month == 11)) System.out.println("The season is Fall"); else if ( (month == 3) && (day <= 19 )) System.out.println("The season is Winter"); else if ( (month == 3) && (day >= 20 )) System.out.println("The season is Spring"); else if ( (month == 6) && (day <= 20 )) System.out.println("The season is Spring"); else if ( (month == 6) && (day >= 21 )) System.out.println("The season is Summer"); else if ( (month == 9) && (day <= 20 )) System.out.println("The season is Summer"); else if ( (month == 9) && (day >= 21 )) System.out.println("The season is Autumn"); else if ( (month == 12) && (day <= 21 )) System.out.println("The season is Autumn"); else if ( (month == 12) && (day >= 22 )) System.out.println("The season is Winter"); } }
尝试使用哈希表或枚举。 您可以将日期转换为某个值（jan 1为1，…），然后为某个字段创建bin。 或者你可以用月份做一个枚举。 {1月：冬天，2月：冬天，… 7月：夏天等}
因为在这个范围内所有季节都是整整几个月，你可以用你的约会月份来切换：
switch (date.getMonth()) { case Calendar.JANUARY: case Calendar.FEBRUARY: return "winter"; case Calendar.MARCH: return "spring"; //etc }
我建议使用所有12个日历常量完成整个开关，而不是最后一个的默认值。 然后，您可以确保输入正确，例如
default: throw new IllegalArgumentException();
在末尾。
您可能还希望在本季使用枚举，而不是简单的字符串，具体取决于您的用例。
请注意，不推荐使用Date.getMonth（）方法，而应使用java.util.Calendar.get（Calendar.MONTH）。 （只需使用calendar.setDate（yourDate）将日期转换为日历）
简单解决方案
Calendar calendar = Calendar.getInstance(); calendar.setTimeInMillis(timeInMills); int month = calendar.get(Calendar.MONTH); CurrentSeason = month == 11 ? 0 : (month + 1) / 3;