在JAVA中创建一周中的几天的自定义集合

本文介绍了在JAVA中创建一周中的几天的自定义集合的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我想要这样的自定义日历：

I want a custom calendar like this:

enum TradingDays {Monday, Tuesday, Wednesday, Thursday, Friday};

然后我需要遍历它，检查一个特定的枚举元素是否是TODAY的星期几。问题是，JAVA日历与我的日历中的星期几不匹配。所以：

Then I need to iterate over it and check if a particular enum element is the day of week TODAY. The problem is that the JAVA calendar does not match to days of week from my calendar. So:

Calendar now = Calendar.getInstance(); TradingDays.Monday is not equal to any of now.get(Calendar.DAY_OF_WEEK);

那么如何从我的日历TradingDays分配星期一，星期二等同一类型整数值）来自JAVA日历？

So how do I assign Monday, Tuesday etc from my calendar TradingDays the same type (in this case an integer value) from the JAVA calendar?

PS我需要有这样的日历TradingDays喜欢，因为它然后显示给用户，所以他/她选择交易的日子。

P.S. I need to have that calendar TradingDays like that because it is then shown to the user so he/she chooses on which days to trade.

推荐答案

tl; dr

tl;dr

Set<DayOfWeek> tradingDays = EnumSet.range( DayOfWeek.MONDAY , DayOfWeek.FRIDAY ) ; // Mon, Tue, Wed, Thu, & Fri. Boolean todayIsTradingDay = tradingDays.contains( LocalDate.now( ZoneId.of( "America/Montreal" ) ).getDayOfWeek() ) ;

详情

Java。

Details

This functionality is built into Java.

Java包括 java.time.DayOfWeek 枚举。

Java includes the java.time.DayOfWeek enum.

传递此枚举的对象，而不是整数1-7，以使您的代码更自我记录，提供类型安全，并确保一系列有效值。

Pass around objects of this enum rather than mere integers 1-7 to make your code more self-documenting, provide type-safety, and ensure a range of valid values.

invoices.printReportForDayOfWeek( DayOfWeek.MONDAY );

周一至周日的编号为1-7，每 ISO 8601 标准。

Numbering is 1-7 for Monday to Sunday, per ISO 8601 standard.

通过调用 getDisplayName 。

String output = DayOfWeek.MONDAY.getDisplayName( TextStyle.FULL , Locale.CANADA_FRENCH ) ; // Or Locale.US, etc.

星期对象集合

要跟踪一周中的多天，请使用 EnumSet （实现 设置 ）或 EnumMap （实施 Map ）。

Collection of day-of-week objects

To track multiple days of the week, use an EnumSet (implementation of Set) or EnumMap (implementation of Map).

Set<DayOfWeek> weekend = EnumSet.of( DayOfWeek.SATURDAY , DayOfWeek.SUNDAY ) ; … Boolean todayIsWeekend = weekend.contains( LocalDate.now( ZoneId.of( "America/Montreal" ) ).getDayOfWeek() ) ;

或者在这个问题的情况下，特别是一个工作日的集合。如果定义在应用程序执行期间没有改变，则可以定义为静态最终常数。

Or in the case of this Question specifically, a collection of the weekdays. Perhaps define as a static final constant if the definition does not change during execution of the app.

static final Set<DayOfWeek> tradingDays = EnumSet.of( DayOfWeek.MONDAY , DayOfWeek.TUESDAY , DayOfWeek.WEDNESDAY , DayOfWeek.THURSDAY , DayOfWeek.FRIDAY ) ;

或者通过将EnumSet定义为按顺序定义的枚举对象范围，使它更短。指定MONDAY& FRIDAY并让 EnumSet 填写之间的值。使用 EnumSet .range 。

Or make that even shorter by defining an EnumSet as a range of enum objects defined in a sequential order. Specify MONDAY & FRIDAY and let EnumSet fill in the values in between. Use EnumSet.range.

static final Set<DayOfWeek> tradingDays = EnumSet.range( DayOfWeek.MONDAY , DayOfWeek.FRIDAY ) ; // Mon, Tue, Wed, Thu, & Fri.

然后测试今天。请注意，时区对于确定当前日期至关重要。

Then test for today. Note that a time zone is crucial in determining the current date. For any given moment the date varies around the globe by zone.

ZoneId zoneId = ZoneId.of( "America/Montreal" ) ; LocalDate today = LocalDate.now( zoneId ) ; DayOfWeek todayDow = today.getDayOfWeek() ; Boolean todayIsTradingDay = tradingDays.contains( todayDow ).getDayOfWeek() ) ;

关于java.time java.time 框架内置于Java 8及以后。这些类取代了旧的麻烦的日期时间类，例如 java.util.Date ， .Calendar java.text.SimpleDateFormat 。

About java.time

The java.time framework is built into Java 8 and later. These classes supplant the old troublesome date-time classes such as java.util.Date, .Calendar, & java.text.SimpleDateFormat.

Joda-Time 专案，现在位于维护模式中，建议您迁移到java.time。

The Joda-Time project, now in maintenance mode, advises migration to java.time.

要了解详情，请参阅 Oracle教程 。并且搜索Stack Overflow的很多例子和解释。

To learn more, see the Oracle Tutorial. And search Stack Overflow for many examples and explanations.

很多java.time功能都支持Java 6& 7在 ThreeTen-Backport 中，并进一步修改为 ThreeTenABP 中的org / wiki / Android_（operating_system） =nofollow> Android 。

Much of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport and further adapted to Android in ThreeTenABP.

ThreeTen-Extra 专案使用附加类扩展java.time。这个项目是将来可能增加java.time的一个证明。您可以在这里找到一些有用的类，例如 Interval ， YearWeek ， YearQuarter 等等。

The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.