Java日期格式转换成星期几

日期格式YYYY-MM-DD:

//Java日期格式转换成星期几 yyyy-MM-dd
    public static String  dateToWeek(String datetime) throws ParseException {
        String rq = datetime;
        String[] weekDays = {"星期日", "星期一", "星期二", "星期三", "星期四", "星期五", "星期六"};
        Date date = new SimpleDateFormat("yyyy-MM-dd").parse(rq);
        Calendar cal = Calendar.getInstance();
        cal.setTime(date);
        int w = cal.get(Calendar.DAY_OF_WEEK) - 1 < 0 ? 0 : cal.get(Calendar.DAY_OF_WEEK) - 1;
        String week= weekDays[w];
        return week;
    }

执行结果：