Calander获取一天所在周的第一天和最后一天

public static String getFirstAndLastOfWeek(String dataStr) throws ParseException {
        Calendar cal = Calendar.getInstance();

        cal.setTime(new SimpleDateFormat("yyyy-MM-dd").parse(dataStr));

        int d = 0;
        if (cal.get(Calendar.DAY_OF_WEEK) == 1) {
            d = -6;
        } else {
            d = 2 - cal.get(Calendar.DAY_OF_WEEK);
        }
        cal.add(Calendar.DAY_OF_WEEK, d);
        // 所在周开始日期
        String data1 = new SimpleDateFormat("yyyy/MM/dd").format(cal.getTime());
        cal.add(Calendar.DAY_OF_WEEK, 6);
        // 所在周结束日期
        String data2 = new SimpleDateFormat("yyyy/MM/dd").format(cal.getTime());
        return data1 + "-" + data2;

    }