java - 如何获得前一周的数字

Question

我需要得到前一周的号码。例如，这是第 38 周，我需要获得第 37 周。如何最好地进行？

int currentWeekNumber= now.get(Calendar.WEEK_OF_YEAR);
int previousWeekNum = // How to get the previous week number??

    System.out.println("currentWeekNum = " + currentWeekNumber);
    System.out.println(" previousWeekNum = " + previousWeekNum);

Answer 1

这对我来说很好......这是获得它的正确语法

Calendar now = Calendar.getInstance();

    int currentWeek = now.get(Calendar.WEEK_OF_YEAR);
    System.out.println("current week = " + currentWeek);

now.add(Calendar.WEEK_OF_YEAR, -1);
    int test = now.get(Calendar.WEEK_OF_YEAR);
    System.out.println(" test date = " + test);

Answer 2

-1 会正常工作吗？

 System.out.println("currentWeekNum = " + currentWeekNumber);
 System.out.println("previousWeekNum = " + currentWeekNumber-1);

旁注：不要忘记检查当前周是否是第一周:)

由于上述解决方案有点模糊，并且正如其他人指出的那样（您也发现），请使用日历的 add 方法，哪个更准确。

cal.add(Calendar.WEEK_OF_YEAR, -1); //Then use this instance.
int preveWeekNum = cal.get(Calendar.WEEK_OF_YEAR);

Answer 3

唯一正确的方法似乎是：

cal.add(Calendar.WEEK_OF_YEAR, -1);
int previousWeekNum = cal.get(Calendar.WEEK_OF_YEAR);

Answer 4

你有 currentWeek 计数。然后 currentWeek -1 将给出前一周。

int previousWeekNum = 0;
calender.add(Calendar.WEEK_OF_YEAR, -1);
previousWeekNum = calender.get(Calendar.WEEK_OF_YEAR);