java计算某个日期是周几

// 1,返回中文    public static String getWeekday(String date) {// 必须yyyy-MM-dd        SimpleDateFormat sd = new SimpleDateFormat("yyyy-MM-dd");        SimpleDateFormat sdw = new SimpleDateFormat("E");        Date d = null;        try {            d = sd.parse(date);        } catch (ParseException e) {            e.printStackTrace();        } catch (Exception e) {            e.printStackTrace();        }        return sdw.format(d);    }    // 2，返回数字    public static int dayForWeek(String pTime) throws Exception {        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");        Calendar c = Calendar.getInstance();        c.setTime(format.parse(pTime));        int dayForWeek = 0;        if (c.get(Calendar.DAY_OF_WEEK) == 1) {            dayForWeek = 7;        } else {            dayForWeek = c.get(Calendar.DAY_OF_WEEK) - 1;        }        return dayForWeek;    }    public static void main(String[] args) {        try {            System.out.println(dayForWeek("2017-5-17"));            System.out.println(getWeekday("2017-5-17"));        } catch (Exception e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }