Java实现输出某天是周几

某天是周几

public static String getWeek(String date) {
        Calendar cal = Calendar.getInstance();
        SimpleDateFormat f = new SimpleDateFormat("yyyymmdd"); //日期格式
        Date d = null;
        try {
            d = f.parse(dates);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        cal.setTime(d);
        int w = cal.get(Calendar.DAY_OF_WEEK) - 1;
        String week = "null";
        switch (w) {
            case 0:
                week = "周日";
                break;
            case 1:
                week = "周一";
                break;
            case 2:
                week = "周二";
                break;
            case 3:
                week = "周三";
                break;
            case 4:
                week = "周四";
                break;
            case 5:
                week = "周五";
                break;
            case 6:
                week = "周六";
                break;

        }
        return week;
    }