Calendar知识点

java.util.Calendar

  • 用于日期和时间的运算
  • 抽象类，不能实例化
  • 瞬间可用毫秒值来表示，它是距历元（即格林威治标准时间 1970年1月1日的00:00:00.000，格里高利历）的偏移量
Calendar rightNow = Calendar.getInstance();

java.util.GregorianCalendar

  • GregorianCalendar(格利高里日期) 是 Calendar 的一个具体子类，提供了世界上大多数国家/地区使用的标准日历系统

实例化GregorianCalendar

Calendar calendar = new GregorianCalendar();

获取年、月、日等

Calendar calendar = new GregorianCalendar();

int year       = calendar.get(Calendar.YEAR);
int month      = calendar.get(Calendar.MONTH);
int dayOfMonth = calendar.get(Calendar.DAY_OF_MONTH); // Jan = 0, not 1
int dayOfWeek  = calendar.get(Calendar.DAY_OF_WEEK);
int weekOfYear = calendar.get(Calendar.WEEK_OF_YEAR);
int weekOfMonth= calendar.get(Calendar.WEEK_OF_MONTH);

int hour       = calendar.get(Calendar.HOUR);        // 12 hour clock
int hourOfDay  = calendar.get(Calendar.HOUR_OF_DAY); // 24 hour clock
int minute     = calendar.get(Calendar.MINUTE);
int second     = calendar.get(Calendar.SECOND);
int millisecond= calendar.get(Calendar.MILLISECOND);

设置年、月、日

Calendar calendar = new GregorianCalendar();

calendar.set(Calendar.YEAR, 2009);
calendar.set(Calendar.MONTH, 11); // 11 = december
calendar.set(Calendar.DAY_OF_MONTH, 24); // christmas eve

添加和减少年、月、日等

Calendar calendar = new GregorianCalendar();

//set date to last day of 2009
calendar.set(Calendar.YEAR, 2009);
calendar.set(Calendar.MONTH, 11); // 11 = december
calendar.set(Calendar.DAY_OF_MONTH, 31); // new years eve

//add one day
calendar.add(Calendar.DAY_OF_MONTH, 1);

//date is now jan. 1st 2010
int year       = calendar.get(Calendar.YEAR);  // now 2010
int month      = calendar.get(Calendar.MONTH); // now 0 (Jan = 0)
int dayOfMonth = calendar.get(Calendar.DAY_OF_MONTH); // now 1

calendar.add(Calendar.DAY_OF_MONTH, -1);

陷阱和误区

月份陷阱

  • 月份从0到11

星期误区

  • 1 = sunday, 2 = monday, …, 7 = Saturday

参考资料

posted on 2016-06-30 13:46  superliu213  阅读(179)  评论(0)    收藏  举报

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