获取本月的开始/结束时间

public static Date getBeginDayOfMonth() {

   // 开始

   Calendar calendar=Calendar.getInstance();

   calendar.set(getNowYear(), getNowMonth()-1, 1);

   return getDayStartTime(calendar.getTime());

   // 结束

   Calendar calendar=Calendar.getInstance();

   calendar.set(getNowYear(), getNowMonth()-1, 1);

   int day = calendar.getActualMaximum(5);

   calendar.set(getNowYear(), getNowMonth()-1, day);

   return getDayEndTime(calendar.getTime());

}