java.time

Question

如何在当前/某个月获取日历中的所有日期？例如本月，如图片

结果是[＆＃34; 07-31-2016＆＃34;，＆＃34; 08-01-2016＆＃34;，＆＃34; 08-02-2016＆＃34; ...＆＃34; 08-31-2016＆＃34;，＆＃34; 09-01-2016＆＃34;，＆＃34; 09-02-2016＆＃34;，＆＃34; 09-03- 2016＆＃34;]

任何想法？，提前谢谢。

Answer 1

好吧，使用Calendar及其常量，您可以轻松实现这一目标：

鉴于month和year获得该月的第一天并在星期一放置日历：

Calendar start = Calendar.getInstance();
start.set(MONTH, month - 1);  // month is 0 based on calendar
start.set(YEAR, year);
start.set(DAY_OF_MONTH, 1);
start.getTime();   // to avoid problems getTime make set changes apply
start.set(DAY_OF_WEEK, SUNDAY);
if (start.get(MONTH) <= (month - 1))  // check if sunday is in same month!
    start.add(DATE, -7);

给定month和year获取月份的最后一天并将日历移至星期日

Calendar end = Calendar.getInstance();
end.set(MONTH, month);  // next month 
end.set(YEAR, year);
end.set(DAY_OF_MONTH, 1);
end.getTime();   // to avoid problems getTime make set changes apply
end.set(DATE, -1);
end.set(DAY_OF_WEEK, SATURDAY);
if (end.get(MONTH) != month)  
    end.add(DATE, + 7);

测试一下：

public static void main(String[] args) {
    int month = 8, year = 2016; 

    Calendar start = Calendar.getInstance();
    start.set(MONTH, month - 1);  // month is 0 based on calendar
    start.set(YEAR, year);
    start.set(DAY_OF_MONTH, 1);
    start.getTime();
    start.set(DAY_OF_WEEK, SUNDAY);
    if (start.get(MONTH) <= (month - 1))  
        start.add(DATE, -7);

    System.out.println(printCalendar(start));

    Calendar end = Calendar.getInstance();
    end.set(MONTH, month);  // next month 
    end.set(YEAR, year);
    end.set(DAY_OF_MONTH, 1);
    end.getTime();
    end.set(DATE, -1);
    end.set(DAY_OF_WEEK, SATURDAY);
    start.getTime();
    if (end.get(MONTH) != month)  
        end.add(DATE, + 7);

    System.out.println(printCalendar(end));
}

结合：

import static java.util.Calendar.*;

和

private final static SimpleDateFormat df = new SimpleDateFormat("yyyy/MM/dd");
private static String printCalendar(Calendar c) {
    return df.format(c.getTime()); 
}

<强>输出：

2016/07/31
2016/09/03

。通过

int month = 5, year = 2015;

<强>输出：

2015/04/26 2015/06/06

现在，只需在Calendar循环中迭代开始+1将Calendar.DATE添加到while（在示例中，我将分为几周以便更清楚）：

int i = 1; while (start.before(end)) { System.out.print(printCalendar(start)); if (i % 7 == 0) { // last day of the week System.out.println(); i = 1; } else { System.out.print(" - "); i++; } start.add(DATE, 1); }

<强>输出：

2015/04/26 - 2015/04/27 - 2015/04/28 - 2015/04/29 - 2015/04/30 - 2015/05/01 - 2015/05/02 2015/05/03 - 2015/05/04 - 2015/05/05 - 2015/05/06 - 2015/05/07 - 2015/05/08 - 2015/05/09 2015/05/10 - 2015/05/11 - 2015/05/12 - 2015/05/13 - 2015/05/14 - 2015/05/15 - 2015/05/16 2015/05/17 - 2015/05/18 - 2015/05/19 - 2015/05/20 - 2015/05/21 - 2015/05/22 - 2015/05/23 2015/05/24 - 2015/05/25 - 2015/05/26 - 2015/05/27 - 2015/05/28 - 2015/05/29 - 2015/05/30 2015/05/31 - 2015/06/01 - 2015/06/02 - 2015/06/03 - 2015/06/04 - 2015/06/05 - 2015/06/06

Answer 2

java.time

您可以使用Java 8及更高版本中内置的漂亮java.time类。上述两种解决方案都可以工作，这是Java 8中的一种方法。可以稍微简化一下，将其拆分只是为了理解。

import java.time.DayOfWeek;
import java.time.LocalDate;
import java.time.temporal.TemporalAdjusters;
import java.util.ArrayList;
import java.util.List;

public class Clazz {
    public static void main(String[] args) throws Exception {
        LocalDate today = LocalDate.now();
        LocalDate firstDayOfTheMonth = today.with(TemporalAdjusters.firstDayOfMonth());
        LocalDate lastDayOfTheMonth = today.with(TemporalAdjusters.lastDayOfMonth());
        LocalDate squareCalendarMonthDayStart = firstDayOfTheMonth
                .with(TemporalAdjusters.previousOrSame(DayOfWeek.SUNDAY));
        LocalDate squareCalendarMonthDayEnd = lastDayOfTheMonth
                .with(TemporalAdjusters.nextOrSame(DayOfWeek.SATURDAY));
        List<LocalDate> totalDates = new ArrayList<>();
        while (!squareCalendarMonthDayStart.isAfter(squareCalendarMonthDayEnd)) {
            totalDates.add(squareCalendarMonthDayStart);
            squareCalendarMonthDayStart = squareCalendarMonthDayStart.plusDays(1);
        }

        totalDates.forEach(System.out::println);
    }
}

Answer 3

在那个月的第一天之前获得星期一：

Calendar c = Calendar.getInstance();
c.setFirstDayOfWeek(Calendar.MONDAY);
c.set(2016, 08, 01);

Calendar start = Calendar.getInstance();
start.setFirstDayOfWeek(Calendar.MONDAY);
start.setWeekDate(2016,c.getWeekYear(), Calendar.MONDAY);

在那个月的最后一天之后获得星期天：

c.set(2016,08,31);
Calendar end = Calendar.getInstance();
end.setFirstDayOfWeek(Calendar.MONDAY);
end.setWeekDate(2016, c.getWeekYear(), Calendar.SUNDAY);

然后打印开始和结束之间的所有日期

Answer 4

像这样写一个常用的方法并使用-

 fun getAllDateOfCurrentMonth(): List<LocalDate> {
            val yearMonth= YearMonth.now()
            val firstDayOfTheMonth = yearMonth.atDay(1)
            val datesOfThisMonth = mutableListOf<LocalDate>()
            for (daysNo in 0 until yearMonth.lengthOfMonth()){
                datesOfThisMonth.add(firstDayOfTheMonth.plusDays(daysNo.toLong()))
            }
            return datesOfThisMonth
        }

获取当月的日历中的所有日期

4 个答案:

java.time