求一个日期算法，着急

Question

需求如下，在当前日期上减去两个工作日（周六周日不算工作日）
eg: 今天是星期一，是15号，我要的结果是上周三，11号。 求详细代码

Answer 1

        Calendar now = GregorianCalendar.getInstance();
        now.add(Calendar.DAY_OF_MONTH , -5);
        
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        
        System.out.println(sdf.format(now.getTime()));
        System.out.println(now.get(Calendar.DAY_OF_WEEK));
        System.out.println(now.get(Calendar.DAY_OF_MONTH));

Answer 2

递归，详细自己写Date d = get2workDayAgo（now, 2）;public Date get2workDayAgo(Date today, int minus) {
   if (minus == 0)
       return today
   if (today is 周日 || today is 周六 || today is 法定假日) 
        return get2workDayAgo（today-1, minus）
   return get2workDayAgo（today - 1, minus - 1）
}

Answer 3

public static Calendar[] calendarArray = new Calendar[]{上周三，上周四，上周五，周一，周二，周三，周四，周五，周六，周日};
function(Calendar calendar) {
     if(周六 == calendar || 周日 == calendar) {
          return calendarArray[5];
     }
     return calendarArray[getCalendarIndexInArray(calendar)-2];
}

Answer 4

public static Calendar[] calendarArray = new Calendar[]{上周三，上周四，上周五，周一，周二，周三，周四，周五，周六，周日};
function(Calendar calendar) {
if(周日 == calendar) {
return calendarArray[5];
}
return calendarArray[getCalendarIndexInArray(calendar)-3];
}刚贴错了，纠正一下~

Answer 5

public static void main(String args[]){
    final String dayNames[] = { "星期日", "星期一", "星期二", "星期三", "星期四", "星期五","星期六" };
    Calendar calendar = Calendar.getInstance(); 
    Date date = new Date(); 
    calendar.setTime(date); 
    int dayOfWeek = calendar.get(Calendar.DAY_OF_WEEK)-1; 
    if(dayOfWeek <0)dayOfWeek=0; 
    System.out.println("Today is:"+dayNames[dayOfWeek]);
    if(dayNames[dayOfWeek].equals("星期日")||dayNames[dayOfWeek].equals("星期二")){
        calendar.add(Calendar.DAY_OF_MONTH, -3);
    }
    else if(dayNames[dayOfWeek].equals("星期一")){
        calendar.add(Calendar.DAY_OF_MONTH, -4);
    }
    else{
        calendar.add(Calendar.DAY_OF_MONTH, -2);
    }
    System.out.println(calendar.getTime());
  }    
帮忙看看 这个行不行

Answer 6

Calendar today =  Calendar.getInstance();
int week = today.get(Calendar.DAY_OF_WEEK);
int rq = today.get(Calendar.DAY_OF_MONTH);
//如果是周一、周二、周三，需要减去四天
if(week==2 || week==3 || week==4){
week = week-5;
rq = rq-5;
}
//如果是周六，需要减去三天
else if(week == 1){
week = week-4;
rq = rq-4;
}else{
week = week-3;
rq = rq-3;
}
//如星期处理
week= week<0?week+7:week;
System.out.println("今天是" + rq + "号，星期" + (week-1));

Answer 7

public static void main(String[] args) {
Date date=new Date();
Calendar ca=Calendar.getInstance();
ca.setTime(date);
System.out.println(ca.get(Calendar.YEAR)+"-"+(ca.get(Calendar.MONTH)+1)+"-"+ca.get(Calendar.DAY_OF_MONTH));
        for(int i=0;i<2;){
         ca.add(Calendar.DAY_OF_MONTH, -1);
         if(ca.get(Calendar.DAY_OF_WEEK)!=7 && ca.get(Calendar.DAY_OF_WEEK)!=1)
         i++;
        }
        System.out.println(ca.get(Calendar.YEAR)+"-"+(ca.get(Calendar.MONTH)+1)+"-"+ca.get(Calendar.DAY_OF_MONTH));
}

Answer 8

方法比较笨，直接判断，不过经过验证    Calendar today =  Calendar.getInstance();
    int week = today.get(Calendar.DAY_OF_WEEK);
     int rq = today.get(Calendar.DAY_OF_MONTH);
//如果是周一、周二、周三，需要减去四天
if(week==2 || week==3 || week==4){
week = week-5;
rq = rq-5;
}
//如果是周六，需要减去三天
else if(week == 1){
week = week-4;
rq = rq-4;
}else{
week = week-3;
rq = rq-3;
}
//如星期处理
week= week<0?week+7:week;
System.out.println("今天是" + rq + "号，星期" + (week-1));