获取一周的第一个日期 [英] fetch the first date of the week

问题描述

我想在java中使用日历和日期获取本周的第一个日期，输入为::
1.每月的周数
2.月
3.年

I want to fetch the first date of the week in java using Calendar and Date with the inputs as :: 1. Week number of the month 2. Month 3. year

    Calendar cal = Calendar.getInstance();
    int weekOfMonth = Calendar.WEEK_OF_MONTH;
    System.out.println("weekOfMonth : " + weekOfMonth);

此后我不知道继续。

推荐答案

Calendar类中有一个方法getFirstDayOfWeek（），它将返回0表示星期日，1表示星期一等等。以下代码片段基于此，并将给你一周的第一个日期。

There is a method getFirstDayOfWeek() in Calendar class that will return the day in 0 for Sunday, 1 for Monday and so on.The following code snippet is based on this and will give you the first date of the week.

private static Date getFirstDateOfWeek(){
        Calendar cal = Calendar.getInstance(); 
        Date d = Calendar.getInstance().getTime();
        int currDay  =  d.getDay(); // getting the current day
        int startDay =  (currDay - cal.getFirstDayOfWeek()) + 1; // calculate the difference of number days to the current date from the first day of week
        d.setDate(d.getDate() - startDay); // setting the date accordingly.
        return d;
    }

希望这会对你有帮助。

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