Question

我需要找到上个月的上周五。这个月是六月。我需要五月的最后一个星期五。在这种情况下（5月29日）。我只能找到当月的上周五。在我找到上个月的星期五之后，我需要检查它已经过了多少天。如果自上周五起已经过了5天，则执行任务。希望这很清楚。如果没有，请询问，我可以更详细地解释。

public class task {

static String lastFriday;
static String dtToday;

public static void main(String[] args) {
   //daysInBetween = current day - (last month's friday date)

   if (daysInBetween = 5) {
      //run program after 5 days
   } else { //quit program }
}

// Gets last Friday of the Month
// Need last Friday of previous Month...
public static String getLastFriday() {
    Calendar cal = new GregorianCalendar();
    cal.set(GregorianCalendar.DAY_OF_WEEK, Calendar.FRIDAY);
    cal.set(GregorianCalendar.DAY_OF_WEEK_IN_MONTH, -1);        
    SimpleDateFormat date_format = new SimpleDateFormat("yyyy/MM/dd");
    lastFriday = date_format.format(cal.getTime()); 
    return lastFriday;
}

// Gets today's date
public static String getToday() {
    Calendar cal = new GregorianCalendar();     
    SimpleDateFormat date_format = new SimpleDateFormat("yyyy/MM/dd");      
    dtToday = date_format.format(cal.getTime());    
    return dtToday;
}
}

Answer 1

使用方法

查找last Friday of any month

public Date getLastFriday( int month, int year ) {
   Calendar cal = Calendar.getInstance();
   cal.set( year, month + 1, 1 );
   cal.add( Calendar.DAY_OF_MONTH, -( cal.get( Calendar.DAY_OF_WEEK ) % 7 + 1 ) );
   return cal.getTime();
}

您可以使用以下方法查找2天之间的差异 -

public int getDifferenceDays(Date d1, Date d2) {
   int daysdiff=0;

   long diff = d2.getTime() - d1.getTime();
   long diffDays = diff / (24 * 60 * 60 * 1000)+1;
   daysdiff = (int) diffDays;

   return daysdiff;
 }

Answer 2

你快到了，只需在你的getLastFriday方法中添加以下内容：

// Gets last Friday of the Month
// Need last Friday of previous Month...
public static String getLastFriday() {
    Calendar cal = new GregorianCalendar();
    // reduce the "current" month by 1 to get the "previous" month
    cal.set(GregorianCalendar.MONTH, cal.get(GregorianCalendar.MONTH) - 1); 
    cal.set(GregorianCalendar.DAY_OF_WEEK, Calendar.FRIDAY);
    cal.set(GregorianCalendar.DAY_OF_WEEK_IN_MONTH, -1);        
    SimpleDateFormat date_format = new SimpleDateFormat("yyyy/MM/dd");
    lastFriday = date_format.format(cal.getTime()); 
    return lastFriday;
}

然后，您可以阅读其中一个问题及其答案，以便在几天内获得差异：Finding days difference in java或Calculating the difference between two Java date instances。

找到上个月的最后一个星期五，查看当前日期之间的天数

2 个答案: