java获取当前日期是星期几

DateFormat df = new SimpleDateFormat("yyyy-MM-dd");
String dateStr = df.format(new Date())+"是";
Calendar calendar = Calendar.getInstance();
calendar.setTime(new Date());
int dayOfWeek = calendar.get(Calendar.DAY_OF_WEEK);
if(dayOfWeek == Calendar.MONDAY){// 周一
    dateStr += "周一";
}
if(dayOfWeek == Calendar.TUESDAY){// 周二
    dateStr += "周二";
}
if(dayOfWeek == Calendar.WEDNESDAY){// 周三
    dateStr += "周三";
}
if(dayOfWeek == Calendar.THURSDAY){// 周四
    dateStr += "周四";
}
if(dayOfWeek == Calendar.FRIDAY){// 周五
    dateStr += "周五";
}
if(dayOfWeek == Calendar.SATURDAY){// 周六
    dateStr += "周六";
}
if(dayOfWeek == Calendar.SUNDAY){// 周日
    dateStr += "周日";
}
System.out.println(dateStr);