Java data ×ܽá

1.¼ÆËãijһÔ·ݵÄ×î´óÌìÊý
Calendar time=Calendar.getInstance();
time.clear();
time.set(Calendar.YEAR,year); //year Ϊ int
time.set(Calendar.MONTH,i-1);//×¢Òâ,Calendar¶ÔÏóĬÈÏÒ»ÔÂΪ0
int day=time.getActualMaximum(Calendar.DAY_OF_MONTH);//±¾Ô·ݵÄÌìÊý
×¢£ºÔÚʹÓÃset·½·¨Ö®Ç°£¬±ØÐëÏÈclearһϣ¬·ñÔòºÜ¶àÐÅÏ¢»á¼Ì³Ð×Ôϵͳµ±Ç°Ê±¼ä
2.CalendarºÍDateµÄת»¯
(1) Calendarת»¯ÎªDate
Calendar cal=Calendar.getInstance();
Date date=cal.getTime();
(2) Dateת»¯ÎªCalendar
Date date=new Date();
Calendar cal=Calendar.getInstance();
cal.setTime(date);
3.¸ñʽ»¯Êä³öÈÕÆÚʱ¼ä £¨Õâ¸öÓõıȽ϶ࣩ
Date date=new Date();
SimpleDateFormat df=new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
String time=df.format(date);
System.out.println(time);
4.¼ÆËãÒ»ÄêÖеĵڼ¸ÐÇÆÚ
(1)¼ÆËãijһÌìÊÇÒ»ÄêÖеĵڼ¸ÐÇÆÚ
Calendar cal=Calendar.getInstance();
cal.set(Calendar.YEAR, 2006);
cal.set(Calendar.MONTH,;
cal.set(Calendar.DAY_OF_MONTH, 3);
int weekno=cal.get(Calendar.WEEK_OF_YEAR);
(2)¼ÆËãÒ»ÄêÖеĵڼ¸ÐÇÆÚÊǼ¸ºÅ
SimpleDateFormat df=new SimpleDateFormat("yyyy-MM-dd");
Calendar cal=Calendar.getInstance();
cal.set(Calendar.YEAR, 2006);
cal.set(Calendar.WEEK_OF_YEAR, 1);
cal.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
System.out.println(df.format(cal.getTime()));
Êä³ö:
2006-01-02
5.add()ºÍroll()µÄÓ÷¨(²»Ì«³£ÓÃ)
(1)add()·½·¨
SimpleDateFormat df=new SimpleDateFormat("yyyy-MM-dd");
Calendar cal=Calendar.getInstance();
cal.set(Calendar.YEAR, 2006);
cal.set(Calendar.MONTH,;
cal.set(Calendar.DAY_OF_MONTH, 3);
cal.add(Calendar.DATE, -4);
Date date=cal.getTime();
System.out.println(df.format(date));
cal.add(Calendar.DATE, 4);
date=cal.getTime();
System.out.println(df.format(date));
Êä³ö£º
2006-08-30
2006-09-03
(2)roll·½·¨
cal.set(Calendar.YEAR, 2006);
cal.set(Calendar.MONTH,;
cal.set(Calendar.DAY_OF_MONTH, 3);
cal.roll(Calendar.DATE, -4);
date=cal.getTime();
System.out.println(df.format(date));
cal.roll