1. public static int dayForWeek(String pTime) throws Exception {
2. format = new SimpleDateFormat("yyyy-MM-dd");
3. Calendar c = Calendar.getInstance();
4. c.setTime(format.parse(pTime));
5. int dayForWeek = 0;
6. if(c.get(Calendar.DAY_OF_WEEK) == 1){
7. dayForWeek = 7;
8. }else{
9. dayForWeek = c.get(Calendar.DAY_OF_WEEK) - 1;
10. }
11. return dayForWeek;
12. }

1. public static int dayForWeek(String pTime) throws Throwable {
2. SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
3. Date tmpDate = format.parse(pTime);
4. Calendar cal = new GregorianCalendar();
5. cal.set(tmpDate.getYear(), tmpDate.getMonth(), tmpDate.getDay());
6. return cal.get(Calendar.DAY_OF_WEEK);
7. }
   

int w = cal.get(Calendar.DAY_OF_WEEK) - 1;
if (w < 0)
w = 0;

return weekDays[w];
}

public static String getWeekOfDate(Date dt) {
String[] weekDays = {"星期日", "星期一", "星期二", "星期三", "星期四", "星期五", "星期六"};
Calendar cal = Calendar.getInstance();
cal.setTime(dt);

int w = cal.get(Calendar.DAY_OF_WEEK) - 1;
if (w < 0)
w = 0;

return weekDays[w];
}

Date date=new Date();
//今天是几号
int day=date.getDate();
System.out.println("Today is :"+day+"号");
Calendar c=Calendar.getInstance();
c.setTime(date);
//今天是这个星期的第几天
int week=c.get(Calendar.DAY_OF_WEEK);
System.out.println("week:"+c.get(Calendar.DAY_OF_WEEK));
//当前月的最后一天是几号
int lastday=c.getActualMaximum(Calendar.DAY_OF_MONTH);
System.out.println("这个月最后一天是:"+lastday+"号");

转自：http://blog.csdn.net/yucf1988/article/details/6461988