给出形如2012-02-01和2012-04-04这样的两个string,如何用java获得这个时间段内的所有日期

String s1 = "2012-02-01";
		String s2 = "2012-04-04";
		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd"); 
		Date   begin=sdf.parse(s1);      
		Date   end=sdf.parse(s2);      
		double   between=(end.getTime()-begin.getTime())/1000;//除以1000是为了转换成秒      
		double  day=between/(24*3600);
		for(int i = 1;i<=day;i++){

Calendar cd = Calendar.getInstance();   
        cd.setTime(sdf.parse(s1));   
        cd.add(Calendar.DATE, i);//增加一天   
        //cd.add(Calendar.MONTH, n);//增加一个月
        System.out.println(sdf.format(cd.getTime()));
		}