java如何判断指定日期星期几

public static void main(String[] args) throws Throwable {

Date d = DateFormatUtil.convertStrToDate("2017-04-17");

for (int i = 0; i < 100; i++) {

String dstr = DateFormatUtil.convertDateToStr(DateUtil.addDays(d, i));

int xqj = dayForWeek(dstr);

if (Calendar.WEDNESDAY == xqj) {

System.out.println(dstr + "|" + xqj);

}

}

}

public static int dayForWeek(String pTime) throws Throwable {

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

Date tmpDate = format.parse(pTime);

Calendar cal = new GregorianCalendar();

cal.setTime(tmpDate);

return cal.get(Calendar.DAY_OF_WEEK);

}