java - Java 日历类中的 Calendar.WEEK_OF_MONTH 和 Calendar.DAY_OF_WEEK IN MONTH 有什么区别？

Question

Java 的 Calendar 类提供了两个字段:WEEK_OF_MONTH 和 DAY_OF_WEEK_IN_MONTH。有人可以向我解释其中的区别吗？使用以下代码进行测试时，它们似乎都返回相同的值:

Calendar date = Calendar.getInstance();
date.set(2011,5,29);
int weekNo1 = date.get(Calendar.WEEK_OF_MONTH);
int weekNo2 = date.get(Calendar.DAY_OF_WEEK_IN_MONTH);

Answer 1

• Calendar.WEEK_OF_MONTH 仅返回“当前月份的当前周数”
• Calendar.DAY_OF_WEEK 仅返回“从上周日开始的当前周中的当前日期”
• Calendar.DAY_OF_WEEK_IN_MONTH 返回“如果当前日期是一个月中的第 N 天” 说 “如果今天是第 3 个星期三则返回 3在一个月内”

所以我在 2016 年 12 月 21 日写下这篇文章:

这就是我得到的:

Calendar today = Calendar.getInstance();
System.out.println(today.get(Calendar.DAY_OF_WEEK));          //outputs 4, as today is 4th day in this week which started on 18
System.out.println(today.get(Calendar.DAY_OF_WEEK_IN_MONTH)); //outputs 3, as today is "3rd Wednesday of this month". Earlier two wednesday were on 7th and 14th
System.out.println(today.get(Calendar.WEEK_OF_MONTH));        //outputs 4, as currently 4th week of a month is running