求日期算法 怎樣算出某年某月的最后一天?

Question

怎樣算出某年某月的最后一天?

Answer 1

搂住:
 /**
     * Desc:TODO:
     * ljh
     * 2005-10-30
     * @param seeddate
     * @return
     * @throws Exception
     */
    public static String getLastDayOfMonthOfYear(String seeddate) throws Exception
    {
        //这里定义对seeddate的格式化
        DateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");
        String ret="";
        try {
            formatter.format(formatter.parse(seeddate));
            Calendar tempcl=formatter.getCalendar();
            //获得制定月份的最大天数
            int MaxDayOfMonthOfYear=tempcl.getActualMaximum(Calendar.DATE);
            //年月日重新组合
            ret=tempcl.get(Calendar.YEAR)+"-"+
             (tempcl.get(Calendar.MONTH)+1)+"-"+MaxDayOfMonthOfYear;
            //对重新组合的年月日进行yyyy-MM-dd格式化
            ret=formatter.format(formatter.parseObject(ret));
            return ret;
        } catch (Exception ex) {
            //........其他错误处理............
            throw ex;
        }
    }

Answer 2

使用方法:
try{
            String date="2005-7-1";
            System.out.println(getLastDayOfMonthOfYear(date));
            //得2005-07-31;
            
            date="2001-2-1";
            System.out.println(getLastDayOfMonthOfYear(date));
            //得2001-02-28;
        }
        catch(Exception ex)
        {
            
        }