java 获取指定日期30天前的日期

    public static String getThirtyDaysAgo(String time){
        SimpleDateFormat sdf  = new SimpleDateFormat("yyyy-MM-dd");
        String thirtyDays = "";
        Calendar calc =Calendar.getInstance();
        try {
            calc.setTime(sdf.parse(time));
            calc.add(calc.DATE, -30);
            Date minDate = calc.getTime();
            thirtyDays = sdf.format(minDate);
        } catch (ParseException e1) {
            e1.printStackTrace();
        }
        return thirtyDays;
    }```