日历时间加减法

日历时间加减法

1.java.util.Calendar

Calendar 类是一个抽象类，它为特定瞬间与一组诸如 YEAR、MONTH、DAY_OF_MONTH、HOUR 等日历字段之间的转换提供了一些方法，并为操作日历字段（例如获得下星期的日期）提供了一些方法。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。

例:

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1.Calendar cal = Calendar.getInstance();//使用默认时区和语言环境获得一个日历。

2.cal.add(Calendar.DAY_OF_MONTH, -1);//取当前日期的前一天.

3.

4.cal.add(Calendar.DAY_OF_MONTH, +1);//取当前日期的后一天.

5.

6.//通过格式化输出日期

7.java.text.SimpleDateFormat format = new java.text.SimpleDateFormat("yyyy-MM-dd");

8.

9.System.out.println("Today is:"+format.format(Calendar.getInstance().getTime()));

10.

11.System.out.println("yesterday is:"+format.format(cal.getTime()));

Calendar cal = Calendar.getInstance();//使用默认时区和语言环境获得一个日历。

cal.add(Calendar.DAY_OF_MONTH, -1);//取当前日期的前一天.

cal.add(Calendar.DAY_OF_MONTH, +1);//取当前日期的后一天.

//通过格式化输出日期

java.text.SimpleDateFormat format = new java.text.SimpleDateFormat("yyyy-MM-dd");

System.out.println("Today is:"+format.format(Calendar.getInstance().getTime()));

System.out.println("yesterday is:"+format.format(cal.getTime()));

1.Calendar cal = Calendar.getInstance();//使用默认时区和语言环境获得一个日历。

2.cal.add(Calendar.DAY_OF_MONTH, -1);//取当前日期的前一天.

3.

4.cal.add(Calendar.DAY_OF_MONTH, +1);//取当前日期的后一天.

5.

6.//通过格式化输出日期

7.java.text.SimpleDateFormat format = new java.text.SimpleDateFormat("yyyy-MM-dd");

8.

9.System.out.println("Today is:"+format.format(Calendar.getInstance().getTime()));

10.

11.System.out.println("yesterday is:"+format.format(cal.getTime()));

Calendar cal = Calendar.getInstance();//使用默认时区和语言环境获得一个日历。

cal.add(Calendar.DAY_OF_MONTH, -1);//取当前日期的前一天.

cal.add(Calendar.DAY_OF_MONTH, +1);//取当前日期的后一天.

//通过格式化输出日期

java.text.SimpleDateFormat format = new java.text.SimpleDateFormat("yyyy-MM-dd");

System.out.println("Today is:"+format.format(Calendar.getInstance().getTime()));

System.out.println("yesterday is:"+format.format(cal.getTime()));

得到2007-12-25日期:

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1.Calendar calendar = new GregorianCalendar(2007, 11, 25,0,0,0);

2.Date date = calendar.getTime();

3.System.out.println("2007 Christmas is:"+format.format(date));

1.Calendar calendar = new GregorianCalendar(2007, 11, 25,0,0,0);

2.Date date = calendar.getTime();

3.System.out.println("2007 Christmas is:"+format.format(date));

java月份是从0-11,月份设置时要减1.

GregorianCalendar构造方法参数依次为：年，月-1，日，时，分，秒.

取日期的部分:

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1.int year =calendar.get(Calendar.YEAR);

2.

3.int month=calendar.get(Calendar.MONTH)+1;

4.

5.int day =calendar.get(Calendar.DAY_OF_MONTH);

6.

7.int hour =calendar.get(Calendar.HOUR_OF_DAY);

8.

9.int minute =calendar.get(Calendar.MINUTE);

10.

11.int seconds =calendar.get(Calendar.SECOND);

1.int year =calendar.get(Calendar.YEAR);

2.

3.int month=calendar.get(Calendar.MONTH)+1;

4.

5.int day =calendar.get(Calendar.DAY_OF_MONTH);

6.

7.int hour =calendar.get(Calendar.HOUR_OF_DAY);

8.

9.int minute =calendar.get(Calendar.MINUTE);

10.

11.int seconds =calendar.get(Calendar.SECOND);
取月份要加1.

判断当前月份的最大天数:

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1.Calendar cal = Calendar.getInstance();

2.int day=cal.getActualMaximum(Calendar.DAY_OF_MONTH);

3.System.out.println(day);

1.Calendar cal = Calendar.getInstance();

2.int day=cal.getActualMaximum(Calendar.DAY_OF_MONTH);

3.System.out.println(day);

java.util.Date

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1.java.util.Date today=new java.util.Date();

2.System.out.println("Today is "+formats.format(today));

1.java.util.Date today=new java.util.Date();

2.System.out.println("Today is "+formats.format(today));

取当月的第一天:

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1.java.text.SimpleDateFormat format = new java.text.SimpleDateFormat("yyyy-MM-01");

2.java.util.Date firstDay=new java.util.Date();

3.System.out.println("the month first day is "+formats.format(firstDay));

1.java.text.SimpleDateFormat format = new java.text.SimpleDateFormat("yyyy-MM-01");

2.java.util.Date firstDay=new java.util.Date();

3.System.out.println("the month first day is "+formats.format(firstDay));

取当月的最后一天:

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2.Calendar cal = Calendar.getInstance();

3.int maxDay=cals.getActualMaximum(Calendar.DAY_OF_MONTH);

4.java.text.Format formatter3=new java.text.SimpleDateFormat("yyyy-MM-"+maxDay);

5.System.out.println(formatter3.format(cal.getTime()));

2.Calendar cal = Calendar.getInstance();

3.int maxDay=cals.getActualMaximum(Calendar.DAY_OF_MONTH);

4.java.text.Format formatter3=new java.text.SimpleDateFormat("yyyy-MM-"+maxDay);

5.System.out.println(formatter3.format(cal.getTime()));

求两个日期之间相隔的天数:

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1.java.text.SimpleDateFormat format = new java.text.SimpleDateFormat("yyyy-MM-dd");

2.java.util.Date beginDate= format.parse("2007-12-24");

3.java.util.Date endDate= format.parse("2007-12-25");

4.long day=(date.getTime()-mydate.getTime())/(24*60*60*1000);

5.System.out.println("相隔的天数="+day);

1.java.text.SimpleDateFormat format = new java.text.SimpleDateFormat("yyyy-MM-dd");

2.java.util.Date beginDate= format.parse("2007-12-24");

3.java.util.Date endDate= format.parse("2007-12-25");

4.long day=(date.getTime()-mydate.getTime())/(24*60*60*1000);

5.System.out.println("相隔的天数="+day);

一年前的日期:

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1.java.text.Format formatter=new java.text.SimpleDateFormat("yyyy-MM-dd");

2.java.util.Date todayDate=new java.util.Date();

3.long beforeTime=(todayDate.getTime()/1000)-60*60*24*365;

4.todayDate.setTime(beforeTime*1000);

5.String beforeDate=formatter.format(todayDate);

6.System.out.println(beforeDate);

1.java.text.Format formatter=new java.text.SimpleDateFormat("yyyy-MM-dd");

2.java.util.Date todayDate=new java.util.Date();

3.long beforeTime=(todayDate.getTime()/1000)-60*60*24*365;

4.todayDate.setTime(beforeTime*1000);

5.String beforeDate=formatter.format(todayDate);

6.System.out.println(beforeDate);

一年后的日期:

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1.java.text.Format formatter=new java.text.SimpleDateFormat("yyyy-MM-dd");

2.java.util.Date todayDate=new java.util.Date();

3.long afterTime=(todayDate.getTime()/1000)+60*60*24*365;

4.todayDate.setTime(afterTime*1000);

5.String afterDate=formatter.format(todayDate);

6.System.out.println(afterDate);

1.java.text.Format formatter=new java.text.SimpleDateFormat("yyyy-MM-dd");

2.java.util.Date todayDate=new java.util.Date();

3.long afterTime=(todayDate.getTime()/1000)+60*60*24*365;

4.todayDate.setTime(afterTime*1000);

5.String afterDate=formatter.format(todayDate);

6.System.out.println(afterDate);
求10小时后的时间

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1.java.util.Calendar Cal=java.util.Calendar.getInstance();

2.Cal.setTime(dateOper);

3.Cal.add(java.util.Calendar.HOUR_OF_DAY,10);

4.System.out.println("date:"+forma.format(Cal.getTime()));

1.java.util.Calendar Cal=java.util.Calendar.getInstance();

2.Cal.setTime(dateOper);

3.Cal.add(java.util.Calendar.HOUR_OF_DAY,10);

4.System.out.println("date:"+forma.format(Cal.getTime()));

求10小时前的时间

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1.java.util.Calendar Cal=java.util.Calendar.getInstance();

2.Cal.setTime(dateOper);

3.Cal.add(java.util.Calendar.HOUR_OF_DAY,-10);

4.System.out.println("date:"+forma.format(Cal.getTime()));

1.java.util.Calendar Cal=java.util.Calendar.getInstance();

2.Cal.setTime(dateOper);

3.Cal.add(java.util.Calendar.HOUR_OF_DAY,-10);

4.System.out.println("date:"+forma.format(Cal.getTime()));

java.sql.Date

继承自java.util.Date,是操作数据库用的日期类型

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java.sql.Date sqlDate = new java.sql.Date(java.sql.Date.valueOf("2007-12-25").getTime());

java.sql.Date sqlDate = new java.sql.Date(java.sql.Date.valueOf("2007-12-25").getTime());

日期比较:简单的比较可以以字符串的形式直接比较,也可使用

java.sql.Date.valueOf("2007-03-08").compareTo(java.sql.Date.valueOf("2007-03-18")) 方式来比较日期的大小.也可使用java.util.Date.after(java.util.Date)来比较.

相差时间：

long difference=c2.getTimeInMillis()-c1.getTimeInMillis();

相差天数：long day=difference/(3600*24*1000)

相差小时：long hour=difference/(3600*1000)

相差分钟：long minute=difference/(60*1000)

相差秒： long second=difference/1000

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1.DateFormat df=new SimpleDateFormat("yyyy-MM-dd EE hh:mm:ss");

2.System.out.println(df.format(new Date()));

3.Date date = new Date();

4.DateFormat shortDate=DateFormat.getDateTimeInstance(DateFormat.SHORT, DateFormat.SHORT);

5.DateFormat mediumDate =DateFormat.getDateTimeInstance(DateFormat.MEDIUM, DateFormat.MEDIUM);

6.DateFormat longDate =DateFormat.getDateTimeInstance(DateFormat.LONG, DateFormat.LONG);

7.DateFormat fullDate =DateFormat.getDateTimeInstance(DateFormat.FULL, DateFormat.FULL);

8.

9.system.out.println(shortDate.format(date));

10.System.out.println(mediumDate.format(date));

11.System.out.println(longDate.format(date));

12.System.out.println(fullDate.format(date));

13.

14.08-4-15 下午3:24

15.2008-4-15 15:24:31

16.2008年4月15日 下午03时24分31秒

17.2008年4月15日 星期二 下午03时24分31秒CST

18.

19.

20.Calendar c = Calendar.getInstance();

21.

22.c.add(Calendar.MONTH, 1); // 目前时间加1个月

23.System.out.println(df.format(c.getTime()));

24.

25.c.add(Calendar.HOUR, 3); // 目前时间加3小时

26.System.out.println(df.format(c.getTime()));

27.

28.c.add(Calendar.YEAR, -2); // 目前时间减2年

29.System.out.println(df.format(c.getTime()));

30.

31.c.add(Calendar.DAY_OF_WEEK, 7); // 目前的时间加7天

32.System.out.println(df.format(c.getTime()));