Java教程-Java DayOfWeek枚举类

Java DayOfWeek枚举类

在Java中，DayOfWeek是一个枚举类，表示一周的7天。除了枚举名称，每个星期都有一个int值。

Java DayOfWeek枚举类声明

让我们来看一下java.time.DayOfWeek的声明。

public enum DayOfWeek extends Enum<DayOfWeek> implements TemporalAccessor, TemporalAdjuster

枚举常量

常量	描述
SUNDAY	星期日的枚举实例
MONDAY	星期一的枚举实例
TUESDAY	星期二的枚举实例
WEDNESDAY	星期三的枚举实例
THURSDAY	星期四的枚举实例
FRIDAY	星期五的枚举实例
SATURDAY	星期六的枚举实例

Java DayOfWeek的方法

方法	描述
int get(TemporalField field)	获取指定字段在此星期几中的值。
boolean isSupported(TemporalField field)	检查是否支持指定字段。
DayOfWeek minus(long days)	返回此星期几之前指定天数的星期几。
DayOfWeek plus(long days)	返回此星期几之后指定天数的星期几。
static DayOfWeek of(int dayOfWeek)	从整数值获取DayOfWeek的实例。
static DayOfWeek[] values()	返回包含此枚举类型的常量的数组，按照它们声明的顺序。
Temporal adjustInto(Temporal temporal)	将指定的时间对象调整为此星期几。
long getLong(TemporalField field)	从此星期几中获取指定字段的值。
String getDisplayName(TextStyle style, Locale locale)	获取文本表示形式，如'Mon'或'Friday'。
int getValue()	获取星期几的整数值。
R query(TemporalQuery query)	使用指定的查询查询此星期几。
ValueRange range(TemporalField field)	获取指定字段的有效值范围。
static DayOfWeek valueOf(String name)	返回具有指定名称的枚举常量。

继承自类java.lang.Enum的方法

1. clone
2. compareTo
3. equals
4. finalize
5. getDeclaringClass
6. hashCode
7. name
8. ordinal
9. toString
10. valueOf

Java DayOfWeek示例：get()

DayOfWeekExample1.java

import java.time.*;
import java.time.temporal.ChronoField;
public class DayOfWeekExample1 {
   public static void main(String[] args) {
      LocalDate localDate = LocalDate.of(2017, Month.JANUARY, 25);
      DayOfWeek dayOfWeek = DayOfWeek.from(localDate);
      System.out.println(dayOfWeek.get(ChronoField.DAY_OF_WEEK));
   }
}

输出：

3

Java DayOfWeek示例：of()

DayOfWeekExample2.java

import java.time.DayOfWeek;
public class DayOfWeekExample2 {
   public static void main(String[] args) {
      DayOfWeek day = DayOfWeek.of(5);
      System.out.println(day.name());
      System.out.println(day.ordinal());
      System.out.println(day.getValue());
   }
}

输出：

FRIDAY
4
5

Java DayOfWeek示例：plus()

DayOfWeekExample3.java

import java.time.*;
public class DayOfWeekExample3 {
   public static void main(String[] args) {
      LocalDate date = LocalDate.of(2017, Month.JANUARY, 31);
      DayOfWeek day = DayOfWeek.from(date);
      System.out.println(day.getValue());
      day = day.plus(3);
      System.out.println(day.getValue());
   }
}

输出：

2
5

Java DayOfWeek示例：minus()

DayOfWeekExample4.java

import java.time.*;
public class DayOfWeekExample4 {
   public static void main(String[] args) {
      LocalDate date = LocalDate.of(2017, Month.JANUARY, 31);
      DayOfWeek day = DayOfWeek.from(date);
      System.out.println(day.getValue());
      day = day.minus(3);
      System.out.println(day.getValue());
   }
}

输出：

2
6

Java DayOfWeek示例：getValue()

DayOfWeekExample5.java

import java.time.*;
import java.time.DayOfWeek;
public class DayOfWeekExample5 {
   public static void main(String ar[]) {
      LocalDate localDate = LocalDate.of(2021, Month.SEPTEMBER, 13);
      DayOfWeek dayOfWeek = DayOfWeek.from(localDate);
      System.out.println("Day of the Week on" + " 13th September 2021 - " + dayOfWeek.name());
      int val = dayOfWeek.getValue();
      System.out.println("Int Value of " + dayOfWeek.name() + " - " + val);
   }
}

输出：

Day of the Week on 13th September 2021 - MONDAY
Int Value of MONDAY - 1