Java 8： java.time.DayOfWeek

本文内容基于 Oracle Java 官方文档，经过个人实践加以整理积累，仅供参考。

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1 java.time.DayOfWeek 是枚举类型，由 7 个常量组成，代表了一周七天

/* =================== 示例代码 =================== */ package test; import java.time.DayOfWeek; import org.junit.Test; public class DateTimeTest { @Test public void test() { System.out.println("DayOfWeek.MONDAY : " + DayOfWeek.MONDAY); System.out.println("DayOfWeek.TUESDAY : " + DayOfWeek.TUESDAY); System.out.println("DayOfWeek.WEDNESDAY : " + DayOfWeek.WEDNESDAY); System.out.println("DayOfWeek.THURSDAY : " + DayOfWeek.THURSDAY); System.out.println("DayOfWeek.FRIDAY : " + DayOfWeek.FRIDAY); System.out.println("DayOfWeek.SATURDAY : " + DayOfWeek.SATURDAY); System.out.println("DayOfWeek.SUNDAY : " + DayOfWeek.SUNDAY); } } /* =================== 测试结果 =================== */ DayOfWeek.MONDAY : MONDAY DayOfWeek.TUESDAY : TUESDAY DayOfWeek.WEDNESDAY : WEDNESDAY DayOfWeek.THURSDAY : THURSDAY DayOfWeek.FRIDAY : FRIDAY DayOfWeek.SATURDAY : SATURDAY DayOfWeek.SUNDAY : SUNDAY

2 整型值范围[1,7]，可以通过加减数字推算

/* =================== 示例代码 =================== */ package test; import java.time.DayOfWeek; import org.junit.Test; public class DateTimeTest { @Test public void test() { System.out.println("周二往前退4天 : " + DayOfWeek.TUESDAY.minus(4)); System.out.println("周五往后进3天 : " + DayOfWeek.FRIDAY.plus(3)); } } /* =================== 测试结果 =================== */ 周二往前退4天 : FRIDAY 周五往后进3天 : MONDAY

3 使用 getDisplayName(TextStyle, Locale) 方法定制字符串内容

/* =================== 示例代码 =================== */ package test; import java.time.DayOfWeek; import java.time.format.TextStyle; import java.util.Locale; import org.junit.Test; public class DateTimeTest { @Test public void test() { System.out.println( DayOfWeek.SUNDAY.getDisplayName(TextStyle.FULL, Locale.CHINESE)); System.out.println( DayOfWeek.SUNDAY.getDisplayName(TextStyle.SHORT, Locale.CHINESE)); System.out.println( DayOfWeek.SUNDAY.getDisplayName(TextStyle.NARROW, Locale.CHINESE)); System.out.println(); System.out.println( DayOfWeek.SUNDAY.getDisplayName(TextStyle.FULL, Locale.ENGLISH)); System.out.println( DayOfWeek.SUNDAY.getDisplayName(TextStyle.SHORT, Locale.ENGLISH)); System.out.println( DayOfWeek.SUNDAY.getDisplayName(TextStyle.NARROW, Locale.ENGLISH)); System.out.println(); System.out.println( DayOfWeek.SUNDAY.getDisplayName(TextStyle.FULL, Locale.FRENCH)); System.out.println( DayOfWeek.SUNDAY.getDisplayName(TextStyle.SHORT, Locale.FRENCH)); System.out.println( DayOfWeek.SUNDAY.getDisplayName(TextStyle.NARROW, Locale.FRENCH)); System.out.println(); System.out.println( DayOfWeek.SUNDAY.getDisplayName(TextStyle.FULL, Locale.GERMANY)); System.out.println( DayOfWeek.SUNDAY.getDisplayName(TextStyle.SHORT, Locale.GERMANY)); System.out.println( DayOfWeek.SUNDAY.getDisplayName(TextStyle.NARROW, Locale.GERMANY)); } } /* =================== 测试结果 =================== */ 星期日 星期日 日 Sunday Sun S dimanche dim. D Sonntag So S