java 遍历某月的所有日期

一、工具类 方法

//获取指定月份的天数    public static int getDaysByYearMonth(int year, int month) {        Calendar a = Calendar.getInstance();        a.set(Calendar.YEAR, year);        a.set(Calendar.MONTH, month - 1);        a.set(Calendar.DATE, 1);        a.roll(Calendar.DATE, -1);        int maxDate = a.get(Calendar.DATE);        return maxDate;    }

二、遍历

    public void dayReport(Date month) {        Calendar cal = Calendar.getInstance();        cal.setTime(month);//month 为指定月份任意日期        int year = cal.get(Calendar.YEAR);        int m = cal.get(Calendar.MONTH);        int dayNumOfMonth = TimeUtils.getDaysByYearMonth(year, m);        cal.set(Calendar.DAY_OF_MONTH, 1);// 从一号开始        for (int i = 0; i < dayNumOfMonth; i++, cal.add(Calendar.DATE, 1)) {            Date d = cal.getTime();            SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd");            String df = simpleDateFormat.format(d);       }    }