直接上代码：

我们的业务是查询当天、当周、当月、当季、当年的记录，所以结束时间直接使用当前时间，就不贴了。

// 今天的开始
public static Date getDayStart() {
    Calendar calendar = Calendar.getInstance();
    calendar.setTime(new Date());
    calendar.set(Calendar.HOUR_OF_DAY, 0);
    calendar.set(Calendar.MINUTE, 0);
    calendar.set(Calendar.SECOND, 0);
    return calendar.getTime();
}
// 本周的开始
public static Date getWeekStart() {
    Calendar calendar = Calendar.getInstance();
    calendar.setTime(getDayStartStamp());
    int dayofweek = calendar.get(Calendar.DAY_OF_WEEK);
    if (dayofweek == 1) {
        dayofweek += 7;
    }
    calendar.add(Calendar.DATE, 2 - dayofweek);
    return calendar.getTime();
}
// 本月的开始
public static Date getMonthStart() {
    Calendar calendar = Calendar.getInstance();
    calendar.setTime(getDayStartStamp());
    calendar.set(Calendar.DAY_OF_MONTH, 1);
    return calendar.getTime();
}
// 本季的开始
public static Date getQuarterStart() {
    Calendar calendar = Calendar.getInstance();
    calendar.setTime(getDayStartStamp());
    int month = calendar.get(Calendar.MONTH);
    if (month < 4) {
        calendar.set(Calendar.MONTH, 0);
    }
    if (month >= 4) {
        calendar.set(Calendar.MONTH, 3);
    }
    if (month >= 7) {
        calendar.set(Calendar.MONTH, 6);
    }
    if (month >= 10) {
        calendar.set(Calendar.MONTH, 9);
    }
    calendar.set(Calendar.DAY_OF_MONTH, 1);
    return calendar.getTime();
}
// 本年的开始
public static Date getYearStart() {
    Calendar calendar = Calendar.getInstance();
    calendar.setTime(getDayStartStamp());
    calendar.set(Calendar.MONTH, 0);
    calendar.set(Calendar.DAY_OF_MONTH, 1);
    return calendar.getTime();
}