/**
 * 取得今天零点的时刻.
 * 
 * @return
 */
public static Date getToday000000() {
    Calendar cal = Calendar.getInstance();
    cal.setTime(new Date());
    cal.set(Calendar.HOUR_OF_DAY, 0);
    cal.set(Calendar.MINUTE, 0);
    cal.set(Calendar.SECOND, 0);
    return cal.getTime();
}