java獲取當月第一天的零點零分和最後一天的23點59分

Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.DAY_OF_MONTH, 1);
//將小時至0
calendar.set(Calendar.HOUR_OF_DAY, 0);
//將分鐘至0
calendar.set(Calendar.MINUTE, 0);
//將秒至0
calendar.set(Calendar.SECOND,0);
//將毫秒至0
calendar.set(Calendar.MILLISECOND, 0);
//獲得當前月第一天
Date sdate = calendar.getTime();
//將當前月加1；
calendar.add(Calendar.MONTH, 1);
//在當前月的下一月基礎上減去1毫秒
calendar.add(Calendar.MILLISECOND, -1);
//獲得當前月最後一天
Date edate = calendar.getTime();

System.out.println("The first day of month=="+sdate.toString());
System.out.println("first day:"+sdate.getTime());
System.out.println("The last day of month=="+edate.toString());
System.out.println("last day:"+edate.getTime());

 作爲備忘，也希望高人給出更優方法