获得指定日期的前一天

/** 
    * 获得指定日期的前一天 
    * @param specifiedDay 
    * @return 
    * @throws Exception 
    */ 
    public static String getSpecifiedDayBefore(String specifiedDay) {
        // SimpleDateFormat simpleDateFormat = new
        // SimpleDateFormat("yyyy-MM-dd");
        Calendar c = Calendar.getInstance();
        Date date = null;
        try {
            date = new SimpleDateFormat("yy-MM-dd").parse(specifiedDay);
        } catch (Exception e) {
            e.printStackTrace();
        }
        c.setTime(date);
        int day = c.get(Calendar.DATE);
        c.set(Calendar.DATE, day - 1);

        String dayBefore = new SimpleDateFormat("yyyy-MM-dd").format(c
                .getTime());
        return dayBefore;
    }