求距现在6个月前的日期

Question

public static Date dateminius(Date datebeforesix){   Calendar date = Calendar.getInstance();
   Calendar dateafter = Calendar.getInstance();
   date.setTime(datebeforesix);
    
   dateafter.set(Calendar.YEAR,date.get(Calendar.YEAR));
   dateafter.set(Calendar.MONTH,date.get(Calendar.YEAR) -6)
   dateafter.set(Calendar.DATE,poiss.get(Calendar.DATE))
   
   Date dateaftersixmonth = dateafter.getTime();   return dateaftersixmonth;}

Answer 1

GregorianCalendar g = new GregorianCalendar(2004,8,31);
      g.add(java.util.Calendar.MONTH,-6);
      System.out.println(g.get(Calendar.MONTH));
      System.out.println(g.get(Calendar.DATE));
      得到的是3， 1号吧

Answer 2

错了  应该是这样 
     应为java里的月份是要减1的
      GregorianCalendar g = new GregorianCalendar(2004,7,31);
      g.add(java.util.Calendar.MONTH,-6);
      System.out.println(g.get(Calendar.MONTH));
      System.out.println(g.get(Calendar.DATE));

Answer 3

DateFormat dateFormat =
        DateFormat.getDateInstance(DateFormat.MEDIUM);
        GregorianCalendar grc=new GregorianCalendar(2004, Calendar.AUGUST,31);
        grc.add(GregorianCalendar.MONTH,-6);
        System.out.println("grc="+dateFormat.format(grc.getTime())); 得出的结果是2/29,8月的个月前应该是2/29没错吧...

Answer 4

catblue(limiaomiao) ：我错了，你的solution是对的。谢谢。