JAVA&Android: 如何显示比当前DATE时间,提前一个月的时间

 

 private String getFrontDate()
    {
       
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        String mDate = "2012-09-12";
        Calendar cal = Calendar.getInstance();
        Date date = null;
        try
        {
            date = sdf.parse(mDate);
        }
        catch (ParseException e)
        {
            e.printStackTrace();
        }

        cal.setTime(date);
        cal.add(Calendar.MONTH, -1);
        Date fDate = cal.getTime();
        mFDate = sdf.format(fDate);
        return mFDate;
       
       
    }