比较两个日期的大小

/**
     * 比较两个日期的大小：
     * 2 发生异常
     * 1 firstDate>secondDate
     * 0 firstDate==secondDate
     * -1 firstDate<secondDate
     * @param format
     * @param firstDate
     * @param secondDate
     * @return 
     */
    public static int compareDate(String format,String firstDate, String secondDate){
        SimpleDateFormat sdf = new SimpleDateFormat(format);
        int result = 2;
        try {
            Date fDate = sdf.parse(firstDate);
            Date sDate = sdf.parse(secondDate);
            
            if(fDate.getTime()>sDate.getTime()){
                result = 1;
            }else if(fDate.getTime()==sDate.getTime()){
                result = 0;
            }else{
                result = -1;
            }
        } catch (ParseException ex) {
            Logger.getLogger(DateUtil.class.getName()).log(Level.SEVERE, null, ex);
        }
        return result;
    }