日期处理

根据月份得到这个月份的最后一天

 

public  String getLastDayOfMonth(String yearMonth) {
    int year = Integer.parseInt(yearMonth.split("-")[0]);  //年
    int month = Integer.parseInt(yearMonth.split("-")[1]); //月
    Calendar cal = Calendar.getInstance();
    // 设置年份
    cal.set(Calendar.YEAR, year);
    // 设置月份
    cal.set(Calendar.MONTH, month - 1);
    // 获取某月最大天数
    int lastDay = cal.getActualMaximum(Calendar.DATE);
    // 设置日历中月份的最大天数
    cal.set(Calendar.DAY_OF_MONTH, lastDay);
    // 格式化日期
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    return sdf.format(cal.getTime());
}

//月份之间的月份

public  List<String> getMonthBetween(String minDate, String maxDate) throws ParseException {
    ArrayList<String> result = new ArrayList<String>();
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM");//格式化为年月

    Calendar min = Calendar.getInstance();
    Calendar max = Calendar.getInstance();

    min.setTime(sdf.parse(minDate));
    min.set(min.get(Calendar.YEAR), min.get(Calendar.MONTH), 1);

    max.setTime(sdf.parse(maxDate));
    max.set(max.get(Calendar.YEAR), max.get(Calendar.MONTH), 2);

    Calendar curr = min;
    while (curr.before(max)) {
        result.add(sdf.format(curr.getTime()));
        curr.add(Calendar.MONTH, 1);
    }

    return result;
}