在一个月内如何找到星期六和星期日？ [英] How can I find Saturdays and Sundays in A given month?

问题描述

我想在一个月内找到所有的星期六和星期日。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

最简单的方式是在所有的日子里迭代这个月，并检查每个星期几。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;
}

我绝对肯定还有更多这样做的有效方法 - 但这是我开始的，并且在发现速度太慢时进行优化。

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时间，这将使你的生活更容易...

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

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