oracle和js和java计算月的第一天与最后一天

oracle查找月的第一天,最后一天 

  SELECT Trunc(Trunc(SYSDATE, 'MONTH') - 1, 'MONTH') First_Day_Last_Month, 
       Trunc(SYSDATE, 'MONTH') - 1 / 86400 Last_Day_Last_Month, 
       Trunc(SYSDATE, 'MONTH') First_Day_Cur_Month, 
       LAST_DAY(Trunc(SYSDATE, 'MONTH')) + 1 - 1 / 86400 Last_Day_Cur_Month 
   FROM dual; 

js计算当月的第一天与最后一天

$(function() {
     var nowdays = new Date();  
     var year = nowdays.getFullYear();
     var month = nowdays.getMonth()+1;
     if(month==0)
     {
         month=12;
         year=year-1;
     }
     if (month < 10) {
         month = "0" + month;
     }
     
     var firstDay = year + "-" + month + "-" + "01";
     var myDate = new Date(year, month, 0);
     var lastDay = year + "-" + month + "-" + myDate.getDate();
 
     var start = $("#ks").val(firstDay)
     var end = $("#js").val(lastDay);

  ));  

java获取当月的开始时间

public static Date getLastMonthStartTime() {  
		Calendar cal = Calendar.getInstance();
		cal.add(Calendar.MONTH, 0);
		cal.set(Calendar.DAY_OF_MONTH,1);//设置为1号,当前日期既为本月第一天 
		cal.set(Calendar.HOUR_OF_DAY, 0);
		cal.set(Calendar.MINUTE, 0);
		cal.set(Calendar.SECOND, 0);
		Date date = cal.getTime();
        
        return date;
    }

java获取上个月的最后一天

	String lastDay = lastMonthDay();
	private String lastMonthDay(){
/*		  Calendar cal = Calendar.getInstance();
		  //下面可以设置月份，注：月份设置要减1，所以设置1月就是1-1，设置2月就是2-1，如此类推
		  cal.set(Calendar.MONTH, 1-1);
		  //调到上个月
		  cal.add(Calendar.MONTH, -1);
		  //得到一个月最最后一天日期(31/30/29/28)
		  int MaxDay=cal.getActualMaximum(Calendar.DAY_OF_MONTH);
		  //按你的要求设置时间
		  cal.set( cal.get(Calendar.YEAR), cal.get(Calendar.MONTH), MaxDay, 23, 59, 59);
		  //按格式输出
		  SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
		  String date = "";
		  date = sdf.format(cal.getTime());*/
		  Calendar c = Calendar.getInstance();
		  c.add(Calendar.MONTH, -1);
		  SimpleDateFormat format =  new SimpleDateFormat("yyyy-MM");
		  String time = format.format(c.getTime());
		//得到一个月最后一天日期(31/30/29/28)
		  int MaxDay=c.getActualMaximum(Calendar.DAY_OF_MONTH);
		  //按你的要求设置时间
		  c.set( c.get(Calendar.YEAR), c.get(Calendar.MONTH), MaxDay, 23, 59, 59);
		  //按格式输出
		  SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
		  String date = sdf.format(c.getTime()); //上月最后一天
		return date;
	}
}