Java 8： java.time.Month__Java

本文內容基於 Oracle Java 官方文檔，經過個人實踐加以整理積累，僅供參考。

1 java.time.Month 是枚舉類型，由 12 個常量組成，代表 1 月至 12 月

/* =================== 範例程式碼 =================== */package test;import java.time.Month;import org.junit.Test;public class DateTimeTest {    @Test    public void test() {        System.out.println("Month.JANUARY   : " + Month.JANUARY);        System.out.println("Month.FEBRUARY  : " + Month.FEBRUARY);        System.out.println("Month.MARCH     : " + Month.MARCH);        System.out.println("Month.APRIL     : " + Month.APRIL);        System.out.println("Month.MAY       : " + Month.MAY);        System.out.println("Month.JUNE      : " + Month.JUNE);        System.out.println("Month.JULY      : " + Month.JULY);        System.out.println("Month.AUGUST    : " + Month.AUGUST);        System.out.println("Month.SEPTEMBER : " + Month.SEPTEMBER);        System.out.println("Month.OCTOBER   : " + Month.OCTOBER);        System.out.println("Month.NOVEMBER  : " + Month.NOVEMBER);        System.out.println("Month.DECEMBER  : " + Month.DECEMBER);    }}/* =================== 測試結果 =================== */Month.JANUARY   : JANUARYMonth.FEBRUARY  : FEBRUARYMonth.MARCH     : MARCHMonth.APRIL     : APRILMonth.MAY       : MAYMonth.JUNE      : JUNEMonth.JULY      : JULYMonth.AUGUST    : AUGUSTMonth.SEPTEMBER : SEPTEMBERMonth.OCTOBER   : OCTOBERMonth.NOVEMBER  : NOVEMBERMonth.DECEMBER  : DECEMBER

2 通過 maxLength() 方法擷取當月最大天數

/* =================== 範例程式碼 =================== */package test;import java.time.Month;import org.junit.Test;public class DateTimeTest {    @Test    public void test() {        System.out.println(" 1月最大天數 : " + Month.JANUARY.maxLength());        System.out.println(" 2月最大天數 : " + Month.FEBRUARY.maxLength());        System.out.println(" 3月最大天數 : " + Month.MARCH.maxLength());        System.out.println(" 4月最大天數 : " + Month.APRIL.maxLength());        System.out.println(" 5月最大天數 : " + Month.MAY.maxLength());        System.out.println(" 6月最大天數 : " + Month.JUNE.maxLength());        System.out.println(" 7月最大天數 : " + Month.JULY.maxLength());        System.out.println(" 8月最大天數 : " + Month.AUGUST.maxLength());        System.out.println(" 9月最大天數 : " + Month.SEPTEMBER.maxLength());        System.out.println("10月最大天數 : " + Month.OCTOBER.maxLength());        System.out.println("11月最大天數 : " + Month.NOVEMBER.maxLength());        System.out.println("12月最大天數 : " + Month.DECEMBER.maxLength());    }}/* =================== 測試結果 =================== */ 1月最大天數 : 31 2月最大天數 : 29 3月最大天數 : 31 4月最大天數 : 30 5月最大天數 : 31 6月最大天數 : 30 7月最大天數 : 31 8月最大天數 : 31 9月最大天數 : 3010月最大天數 : 3111月最大天數 : 3012月最大天數 : 31

3 使用 getDisplayName(TextStyle, Locale) 方法定製字串內容

/* =================== 範例程式碼 =================== */package test;import java.time.Month;import java.time.format.TextStyle;import java.util.Locale;import org.junit.Test;public class DateTimeTest {    @Test    public void test() {        System.out.println(            Month.JANUARY.getDisplayName(TextStyle.FULL, Locale.CHINESE));        System.out.println(            Month.JANUARY.getDisplayName(TextStyle.SHORT, Locale.CHINESE));        System.out.println(            Month.JANUARY.getDisplayName(TextStyle.NARROW, Locale.CHINESE));        System.out.println();        System.out.println(            Month.JANUARY.getDisplayName(TextStyle.FULL, Locale.ENGLISH));        System.out.println(            Month.JANUARY.getDisplayName(TextStyle.SHORT, Locale.ENGLISH));        System.out.println(            Month.JANUARY.getDisplayName(TextStyle.NARROW, Locale.ENGLISH));        System.out.println();        System.out.println(            Month.JANUARY.getDisplayName(TextStyle.FULL, Locale.FRENCH));        System.out.println(            Month.JANUARY.getDisplayName(TextStyle.SHORT, Locale.FRENCH));        System.out.println(            Month.JANUARY.getDisplayName(TextStyle.NARROW, Locale.FRENCH));        System.out.println();        System.out.println(            Month.JANUARY.getDisplayName(TextStyle.FULL, Locale.GERMANY));        System.out.println(            Month.JANUARY.getDisplayName(TextStyle.SHORT, Locale.GERMANY));        System.out.println(            Month.JANUARY.getDisplayName(TextStyle.NARROW, Locale.GERMANY));        System.out.println();    }}/* =================== 測試結果 =================== */一月一月1JanuaryJanJjanvierjanv.JJanuarJanJ