java指定日期的季度以及季度第一天和最后一天（季度统计报表）

获取当前季度，根据月转换到季度：

public static int getQuarterOfYear() {
    Calendar calendar = Calendar.getInstance();
    calendar.setTime(new Date());
    return calendar.get(Calendar.MONTH) / 3 + 1;
}

根据季度获取第一天，从季度到第一个月，再到月的第一天

public static Date getStartDayOfQuarter(int year, int quarter) {

        int startMonth = (quarter - 1) * 3;

        // 根据月获取开始时间
        Calendar cal = Calendar.getInstance();

        cal.set(Calendar.YEAR, year);
        cal.set(Calendar.MONTH, startMonth);
        cal.set(Calendar.DAY_OF_MONTH, 1);

        cal.set(Calendar.HOUR, 0);
        cal.set(Calendar.MINUTE, 0);
        cal.set(Calendar.SECOND, 0);

        return cal.getTime();
}

根据季度获取最后一天，从季度到最后一个月，再到月的最后一天

public static Date getLastDayOfQuarter(int year, int quarter) {

        int lastMonth = quarter * 3 - 1;

        // 根据月获取开始时间
        // 根据月获取开始时间
        Calendar cal = Calendar.getInstance();

        cal.set(Calendar.YEAR, year);
        cal.set(Calendar.MONTH, lastMonth);
        cal.set(Calendar.DAY_OF_MONTH, cal.getActualMaximum(Calendar.DAY_OF_MONTH));

        cal.set(Calendar.HOUR, 0);
        cal.set(Calendar.MINUTE, 0);
        cal.set(Calendar.SECOND, 0);

        return cal.getTime();

    }

测试代码：

public static void main(String[] args) {

        Date startDayOfQuarter = getStartDayOfQuarter(2022, 1);

        System.out.println("startDayOfQuarter = " + startDayOfQuarter);

        Date lastDayOfQuarter = getLastDayOfQuarter(2022, 1);

        System.out.println("lastDayOfQuarter = " + lastDayOfQuarter);
    }