java取得某个月的天数

?

Calendar cal = Calendar.getInstance();cal.set(Calendar.YEAR, Integer.parseInt(year));cal.set(Calendar.MONTH, Integer.parseInt(month) - 1);cal.set(Calendar.DATE, 1);cal.add(Calendar.MONTH, 1);cal.add(Calendar.DATE, -1);int j = cal.get(Calendar.DAY_OF_MONTH);

?