如何找到给定月份的周六和周日? [英] How can I find Saturdays and Sundays in A given month?

问题描述

我想找到给定月份的所有周六和周日.我该怎么做?

I want find all Saturdays and Sundays in A given month. How can I do so?

推荐答案

最简单的方法是遍历一个月中的所有日子，并检查每个日子的星期几.例如:

The simplest way is to just iterate over all the days in the month, and check the day of week for each of them. For example:

// This takes a 1-based month, e.g. January=1. If you want to use a 0-based
// month, remove the "- 1" later on.
public int countWeekendDays(int year, int month) {
    Calendar calendar = Calendar.getInstance();
    // Note that month is 0-based in calendar, bizarrely.
    calendar.set(year, month - 1, 1);
    int daysInMonth = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);

    int count = 0;
    for (int day = 1; day <= daysInMonth; day++) {
        calendar.set(year, month - 1, day);
        int dayOfWeek = calendar.get(Calendar.DAY_OF_WEEK);
        if (dayOfWeek == Calendar.SUNDAY || dayOfweek == Calendar.SATURDAY) {
            count++;
            // Or do whatever you need to with the result.
        }
    }
    return count;
}

我绝对肯定有更有效的方法来做到这一点 - 但这是我要开始的，当我发现它太慢时进行优化.

I'm absolutely sure there are far more efficient ways of doing this - but that's what I'd start with, and optimize when I'd found it's too slow.

请注意，如果您能够使用 Joda Time，您的生活会轻松很多...

Note that if you're able to use Joda Time that would make your life a lot easier...

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