每月获得第三个星期五 [英] Get third friday of a month

问题描述

我正在为我的应用程序开发本地日历。

I am developing a local calendar for my application. but the is an issue with monthly repeat event (day of week).

当我创建从 2016年9月16日开始的事件时（） 2016年9月16日（星期五），然后重复每个月的第三个星期五。但下个月它将在第二个
（2016年10月14日，星期五）创建（这是问题）。

When i am create an event starting on 16-9-2016(16 SEP 2016 FRIDAY) and repeating Third Friday of each month. but next month it create on second Friday 14-10-2016 (This is the issue). next month it will be on third Friday.

我的代码是

public Date nthWeekdayOfMonth(int dayOfWeek, int month, int year, int week, TimeZone timeZone) {
        Calendar calendar = Calendar.getInstance();
        calendar.setTimeZone(timeZone);
        calendar.set(Calendar.DAY_OF_WEEK, dayOfWeek);
        calendar.set(Calendar.WEEK_OF_MONTH, week);
        calendar.set(Calendar.MONTH, month);
        calendar.set(Calendar.YEAR, year);
        return calendar.getTime();
    }

我知道这个问题。但是我不知道如何解决它。.有什么方法可以解决它吗？

I know the issue. but i don`t know how to fix it.. is there any way to fix it ?

推荐答案

您的代码似乎是工作完全正常，据我所见，没有任何问题，可能是您的参数有误。

You code seems to be working completely fine, there is nothing that is going wrong from what I can see, it may be that your parameters are wrong.

请务必注意， MONTH 和 DAY 从0开始，因此， 0 =一月和 0 =周日，因此获取第三个星期五的参数应如下所示：

It is important to note that MONTH and DAY are 0-based so, 0 = January and 0 = Sunday so your parameters for getting the third friday should look like the following:

nthWeekdayOfMonth(6, 9, 2016, 3, TimeZone.getTimeZone("Europe/London"));

将返回以下输出：

Fri Oct 21 11:06:33 BST 2016

要打破下来：

1. 星期几是6，因为星期日= 0。


2. 月是9 -即10月


3. 年份是正常的-2016


4. 周不是基于0的，因此第3周将是索引3


5. TimeZone正常

1. Day of week is 6, because Sunday = 0.
2. Month is 9 - i.e. October
3. Year is normal - 2016
4. Week is NOT 0-based so 3rd week will be index 3
5. TimeZone as normal

请参见日历文档供参考。

因此出于某种原因，它在我的机器上可以工作，但不能在其他机器上工作；我不知道这可能是什么问题，但使用 DAY_OF_WEEK_IN_MONTH 似乎是一个更好的选择：

So for some reason, it works on my machine but it doesn't on others; I don't know what the issue could be with that but using DAY_OF_WEEK_IN_MONTH seems to be a better option for this:

public static Date nthWeekdayOfMonth(int dayOfWeek, int month, int year, int week, TimeZone timeZone) {
    Calendar calendar = Calendar.getInstance();
    calendar.setTimeZone(timeZone);
    calendar.set(Calendar.DAY_OF_WEEK, dayOfWeek);
    //calendar.set(Calendar.WEEK_OF_MONTH, week);
    calendar.set(Calendar.DAY_OF_WEEK_IN_MONTH, week);
    calendar.set(Calendar.MONTH, month);
    calendar.set(Calendar.YEAR, year);
    return calendar.getTime();
}

我通常使用 GregorianCalendar 但 Calendar 应该可以正常工作。

I usually use GregorianCalendar but Calendar should work just fine.

（希望）该应该在大多数情况下都有效，我已经对其进行了测试在其他计算机上以及 ideone 上。

This should (hopefully) work for the most part, I've tested it on other machines and ideone.

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