Calendar的使用
Calendar cal = Calendar.getInstance();

//当前年
int year = cal.get(Calendar.YEAR);


//当前月
int month = (cal.get(Calendar.MONTH))+1;


//当前月的第几天：即当前日
int day_of_month = cal.get(Calendar.DAY_OF_MONTH);


//当前时：HOUR_OF_DAY-24小时制；HOUR-12小时制
int hour = cal.get(Calendar.HOUR_OF_DAY);


//当前分
int minute = cal.get(Calendar.MINUTE);


//当前秒
int second = cal.get(Calendar.SECOND);


//0-上午；1-下午
int ampm = cal.get(Calendar.AM_PM);


//当前年的第几周
int week_of_year = cal.get(Calendar.WEEK_OF_YEAR);


//当前月的第几周
int week_of_month = cal.get(Calendar.WEEK_OF_MONTH);


//当前年的第几天
int day_of_year = cal.get(Calendar.DAY_OF_YEAR);

太好了，谢谢。。