計算某月的最後一天和計算兩個日期之間的天數

計算兩個日期之間相差的天數：

/**  
     * 計算兩個日期之間相差的天數  
     * @param smdate 較小的時間 
     * @param bdate  較大的時間 
     * @return 相差天數 
     * @throws ParseException  
     */    
    public static int daysBetween(Date smdate,Date bdate) throws ParseException    
    {    
        SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");  
        smdate=sdf.parse(sdf.format(smdate));  
        bdate=sdf.parse(sdf.format(bdate));  
        Calendar cal = Calendar.getInstance();    
        cal.setTime(smdate);    
        long time1 = cal.getTimeInMillis();                 
        cal.setTime(bdate);    
        long time2 = cal.getTimeInMillis();         
        long between_days=(time2-time1)/(1000*3600*24);  
            
       return Integer.parseInt(String.valueOf(between_days));           
    }    
      
/** 
*字符串的日期格式的計算 
*/  
    public static int daysBetween(String smdate,String bdate) throws ParseException{  
        SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");  
        Calendar cal = Calendar.getInstance();    
        cal.setTime(sdf.parse(smdate));    
        long time1 = cal.getTimeInMillis();                 
        cal.setTime(sdf.parse(bdate));    
        long time2 = cal.getTimeInMillis();         
        long between_days=(time2-time1)/(1000*3600*24);  
            
       return Integer.parseInt(String.valueOf(between_days));     
    }  
  
}

計算某月的最後一天

/**
     * 獲取某月的最後一天
     * @Title:getLastDayOfMonth
     * @Description:
     * @param:@param year
     * @param:@param month
     * @param:@return
     * @return:String
     * @throws
     */
    public  String getLastDayOfMonth(int year,int month)
    {
        Calendar cal = Calendar.getInstance();
        //設置年份
        cal.set(Calendar.YEAR,year);
        //設置月份
        cal.set(Calendar.MONTH, month-1);
        //獲取某月最大天數
        int lastDay = cal.getActualMaximum(Calendar.DAY_OF_MONTH);
        //設置日曆中月份的最大天數
        cal.set(Calendar.DAY_OF_MONTH, lastDay);
        //格式化日期
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        String lastDayOfMonth = sdf.format(cal.getTime());
         
        return lastDayOfMonth;
    }