public static String DATE_YEAR="YEAR";//年

public static String DATE_MONTH="MONTH";//月

public static String DATE_DAY="DAY";//日

//7天

Date date_day = dateOperation(DATE_DAY,-7);

//1个月

Date date_month = dateOperation(DATE_MONTH,-1);

//1年

Date date_year = dateOperation(DATE_YEAR,-1);

    private Date dateOperation(String dateOperationType,Integer amount) throws Exception {

        Calendar cal = Calendar.getInstance();

        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");

        String s = sdf.format(new Date());

        Date today =  sdf.parse(s);

        cal.setTime(today);

        if (DATE_DAY.equals(dateOperationType)){

            cal.add(cal.DAY_OF_MONTH,amount);

        }

        if (DATE_MONTH.equals(dateOperationType)){

            cal.add(cal.MONTH,amount);

        }

        if (DATE_YEAR.equals(dateOperationType)){

            cal.add(cal.YEAR,amount);

        }

//        System.out.println(cal.getTime());

        return cal.getTime();

    }