取得當月最後一天

JAVA：

public static void main(String[] args) {
SimpleDateFormat sdf = new SimpleDateFormat("dd");
Calendar calendar = Calendar.getInstance();

        System.out.println("today="+sdf.format(calendar.getTime()));
        calendar.add(Calendar.MONTH,1); //Calendar.MONTH 加上1個月(用add    Method)
        System.out.println("nextMonthDay="+sdf.format(calendar.getTime()));
        //第一天
        System.out.println("nextMonthFrist="+sdf.format(getFirstMonthDay(calendar)));
        //最後一天
        System.out.println("nextMonthLast="+sdf.format(getLastMonthDay(calendar)));

}

//每個月的第一天日期
 public static Date getFirstMonthDay(Calendar calendar) {
        calendar.set(Calendar.DATE, calendar.getActualMinimum(Calendar.DATE));
        return calendar.getTime();
 }

 //每個月的最後一天日期
 public static Date getLastMonthDay(Calendar calendar) {
        calendar.set(Calendar.DATE, calendar.getActualMaximum(Calendar.DATE));
        return calendar.getTime();
 }




Javascript：

Date.prototype.Format = function (fmt) {
    var o = {
        "M+": this.getMonth() + 1,
        "d+": this.getDate(),
        "h+": this.getHours(),
        "m+": this.getMinutes(),
        "s+": this.getSeconds(),
        "q+": Math.floor((this.getMonth() + 3) / 3),
        "S": this.getMilliseconds()
    };
    if (/(y+)/.test(fmt)) fmt = fmt.replace(RegExp.$1, (this.getFullYear() + "").substr(4 - RegExp.$1.length));
    for (var k in o)
    if (new RegExp("(" + k + ")").test(fmt)) fmt = fmt.replace(RegExp.$1, (RegExp.$1.length == 1) ? (o[k]) : (("00" + o[k]).substr(("" + o[k]).length)));
    return fmt;
}


function showWeekFirstDay()
{
var Nowdate=new Date();
var WeekFirstDay=new Date(Nowdate-(Nowdate.getDay()-1)*86400000);
alert(WeekFirstDay.Format("yyyy-MM-dd"))
}

function showWeekLastDay()
{
var Nowdate=new Date();
var WeekFirstDay=new Date(Nowdate-(Nowdate.getDay()-1)*86400000);
var WeekLastDay=new Date((WeekFirstDay/1000+6*86400)*1000);
alert(WeekLastDay.Format("yyyy-MM-dd"))
}

function showMonthFirstDay()
{
var Nowdate=new Date();
var MonthFirstDay=new Date(Nowdate.getYear(),Nowdate.getMonth(),1);
alert(MonthFirstDay.Format("yyyy-MM-dd"))
}

function showMonthLastDay()
{
var Nowdate=new Date();
var MonthNextFirstDay=new Date(Nowdate.getYear(),Nowdate.getMonth()+1,1);
var MonthLastDay=new Date(MonthNextFirstDay-86400000);
alert(MonthLastDay.Format("yyyy-MM-dd"))
}






Oracle sql：

select extract(day from last_day(sysdate)) from dual;


SELECT a.HSN_CD,
  a.ITEM_CD,
  A.Item_Nm,
  DECODE(a.ITEM_VAL,'*', to_char(extract(day from last_day(sysdate))) , A.Item_Val) ITEM_VAL,
  A.Item_Cntnt ,
  NVL(B.Hsn_Nm, '共通') Hsn_Nm
FROM TABLENAMEA a
LEFT JOIN TABLENAMEB b
On A.Hsn_Cd    = B.Hsn_Cd
Where A.Hsn_Cd = 'A';