java 如何找到给定月份的星期六和星期日？
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How can I find Saturdays and Sundays in A given month?
提问by Venkat
I want find all Saturdays and Sundays in A given month. How can I do so?
我想找到给定月份中的所有周六和周日。我该怎么做？
回答by Jon Skeet
The simplestway is to just iterate over all the days in the month, and check the day of week for each of them. For example:
在最简单的方法是只迭代所有在一个月的日子里，检查一周的某一天为他们每个人。例如：
// 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;
}
I'm absolutely surethere 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.
我绝对确定有更有效的方法来做到这一点 - 但这是我的开始，并在我发现它太慢时进行优化。
Note that if you're able to use Joda Timethat would make your life a lot easier...
请注意，如果您能够使用Joda Time，那将使您的生活变得更加轻松......
回答by Enrique Marcos
Try this:
试试这个：
import java.util.Calendar;
import java.util.GregorianCalendar;
public class Sundays {
public static void main(String[] args) {
int year = 2012;
// put the month you want
int month = Calendar.JANUARY;
Calendar cal = new GregorianCalendar(year, month, 1);
do {
int day = cal.get(Calendar.DAY_OF_WEEK);
if (day == Calendar.SATURDAY || day == Calendar.SUNDAY) {
System.out.println(cal.get(Calendar.DAY_OF_MONTH));
}
cal.add(Calendar.DAY_OF_YEAR, 1);
} while (cal.get(Calendar.MONTH) == month);
}
}
回答by Bear
Base on the previous answer, I have a small modification When u find the first Saturday and Sunday, you can simply add 7 days to it until the month is changed.
基于之前的答案，我有一个小的修改，当你找到第一个星期六和星期日时，你可以简单地添加7天，直到月份改变。
回答by Prabhat Kumar Kashyap
Please go through this method, I faced a lot finally I created my own.
请通过这种方法，我遇到了很多，最后我创建了自己的方法。
public static int getDayDiff(String dateFrom, String dateTo){ // DD/MM/YYYY
Timestamp tDtF = getTimestampDDmmYYYY(dateFrom);//returning timestamp from / DD/MM/YYYY
Timestamp tDtT = getTimestampDDmmYYYY(dateTo);
Calendar dtF = new GregorianCalendar();
Calendar dtT = new GregorianCalendar();
dtF.setTimeInMillis(tDtF.getTime());
dtT.setTimeInMillis(tDtT.getTime());
int count = 0;
while(dtF.before(dtT)){
count++;
dtF.add(Calendar.DAY_OF_YEAR, 1);
}
return count;
}
public static int countDateSatOrSun(String dateFrom, String dateTo){//DD/MM/YYYY
Timestamp tDtF = getTimestampDDmmYYYY(dateFrom);//returning timestamp from / DD/MM/YYYY
Timestamp tDtT = getTimestampDDmmYYYY(dateTo);
Calendar dtF = new GregorianCalendar();
Calendar dtT = new GregorianCalendar();
dtF.setTimeInMillis(tDtF.getTime());
dtT.setTimeInMillis(tDtT.getTime());
int count = 0;
while(dtF.before(dtT)){
if((dtF.get(Calendar.DAY_OF_WEEK) == Calendar.SATURDAY| dtF.get(Calendar.DAY_OF_WEEK) == Calendar.SUNDAY))
count++;
dtF.add(Calendar.DAY_OF_YEAR, 1);
}
return count;
}
It will give you exact result.
它会给你确切的结果。
