java日期的处理，求助

Question

给出任意年月，得出这个月每周的起止时间例如：2011年01月算出第一周： 2011-1-1   至 2111-1-2第二周： 2011-1-3   至  2011-1-9第三周：  2011-1-10   至  2011-1-16第四周：  2011-1-17   至  2011-1-23第五周： 2011-1-24    至 2011-1-30第六周：  2011-1-31   至  2011-1-31如果没有第五周或第六周 ，则显示  8888-8-8 至 8888-8-8

Answer 1

用Calendar就可以了
for example
import java.util.*;
import java.text.*;
class Test {
    public static void main(String[] args) {
        try {
            String s = "2011-01"; //测试日期
              SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM");
            Calendar c = Calendar.getInstance();
            c.setTime(sdf.parse(s));
            //c.set(Calendar.YEAR, 2011);
            //c.set(Calendar.MONTH, 0);
                    
            c.set(Calendar.DAY_OF_MONTH, 1);
            int week = c.get(Calendar.WEEK_OF_MONTH);
            int month = c.get(Calendar.MONTH);
            String from = "", to = from;
            while (true) {
                if (c.get(Calendar.MONTH) != month) { //月份不同退出循环
                    System.out.printf("%d week: %s - %s\n", week, from, to);
                    break;
                }
                if (from == to) {
                    from = String.format("%tF", c.getTime());
                }
                to = String.format("%tF", c.getTime());
                if (week != c.get(Calendar.WEEK_OF_MONTH)) {
                    System.out.printf("%d week: %s - %s\n", week, from, to);
                    from = to;
                    week++;
                }
                c.add(Calendar.DAY_OF_MONTH, 1);
            }
            for (week=week+1; week<7; week++) { //补足不满6周的
                System.out.printf("%d week: 8888-8-8 - 8888-8-8\n", week);
            }
        } catch (Throwable e) {e.printStackTrace();}
    }
}