用java如何实现某一天是第几周，很急，谢谢您帮忙

Question

因为要做一个排行榜，必须算出某一天的是第几周。用java实现，多谢帮忙

Answer 1

 int     n;   
          GregorianCalendar cal = new GregorianCalendar();
          Calendar da=Calendar.getInstance();
          n=cal.get(GregorianCalendar.DAY_OF_WEEK)-1;
          int d=da.get(Calendar.DATE);
          if   (n==0)   n   =   7;   //今天星期几   
          d   =   d   -   (n-1);   //这个星期一是几号   
          for(n=1;   d>1;   d-=7)   n+=1;   
         System.out.println(n);  

Answer 2

public int getWeekIndexForYear(Date date) {
Calendar c = new GregorianCalendar(date.getYear(), date.getMonth(),
date.getDate());
return c.get(Calendar.WEEK_OF_YEAR);
}public int getWeekIndexForMonth(Date date) {
Calendar c = new GregorianCalendar(date.getYear(), date.getMonth(),
date.getDate());
return c.get(Calendar.WEEK_OF_MONTH);
}

Answer 3

GregorianCalendar cal = new GregorianCalendar();[
System.out.println("今天是本月第:"+cal.get(GregorianCalendar.WEEK_OF_MONTH)+"周");
          System.out.println("今天是本年第:"+cal.get(GregorianCalendar.WEEK_OF_YEAR)+"周");

Answer 4

public class test{
      public static void main(String[] args){
            java.util.Calendar c=java.util.Calendar.getInstance();
            c.set(2007,10,6);//设置为2007年11月6号
            System.out.println(c.getTime());
            System.out.println(c.get(java.util.Calendar.WEEK_OF_YEAR));//获得c代表的日期在当年是第几周
            System.out.println(c.get(java.util.Calendar.WEEK_OF_MONTH));//获得c代表的日期在当月是第几周
      }
}关于Calendar更多的用法，参考jdk api文档