1.Date
/ ** * java.util.Date each instance of a Date * is used to represent a precise time (millisecond accuracy) * internal maintains a long value, since January 1, 1970 the value represented by 00:00:00 Date represents the time between the current elapsed milliseconds. * Design flaw time zone, Date, and therefore most of the developed methods are declared obsolete in the future and then should no longer be used. * / Public class DateDemo { public static void main (String [] args) { Date DATE = new new Date (); System.out.println (DATE); / * * Long the getTime () * Date Gets the milliseconds maintained inside * / Long Time = date.getTime (); System.out.println (Time); date.setTime ( 0 ); System.out.println (DATE); } }
2.SimpleDateFormat
/ ** * the java.text.SimpleDateFormat * may be between the class String and Date are mutually converted according to the specified format. * / Public class SimpleDateFormatDemo1 { public static void main (String [] args) { a Date now = new new a Date (); System.out.println (now); / * * 2019-08-21 10:35:22 * YYYY- dd HH-the mM: mm: SS * / the SimpleDateFormat SDF = new new the SimpleDateFormat ( "the mM-dd-YYYY HH: mm: SS E a" ); / * * the format String (DATE Date) * given Date object according to the current SDF specified date into a string format * / String line = sdf.format(now); System.out.println(line); } }
/ ** * parse a string Date object * / public class SimpleDateFormatDemo2 { public static void main (String [] args) throws a ParseException { String STR = "2008-08-08 20:08:08" ; the SimpleDateFormat SDF = new new the SimpleDateFormat ( "the mM-dd-YYYY HH: mm: SS" ); a Date DATE = sdf.parse (STR); System.out.println (DATE); } }
/ ** * When the program starts, requires users to enter their date of birth in the format: yyyy-MM-dd * then undergo a process of computing output to date a total of how much living * days. And then outputs born 10,000 days of the anniversary of the day is the format of the output of the above. * / Public class the Test { public static void main (String [] args) throws Exception { Scanner Scanner = new new Scanner (System.in); System.out.println ( "Please enter your birthday:" ); String birthStr = Scanner .nextLine (); the SimpleDateFormat SDF = new new the SimpleDateFormat ( "the MM-dd-YYYY" ); a Date Birth = sdf.parse (birthStr); Now DATE = new new DATE (); Long Time = now.getTime () - birth.getTime (); Time = Time / 1000/60/60/24- ; System.out.println ( "Congratulations, you've lived" + time + "Heaven, keep it!" ); Time = birth.getTime () + 1000 * 60 * 60 * * 24-10000L ; a Date DATE = new new a Date (Time); String Line = sdf.format (DATE); System.out .println ( "You were born 10,000 days of the anniversary is:" + Line); } }
3.Calendar
/ ** * Calendar category the java.util.Calendar * Calendar is an abstract class, the method provides a series of calendar-based operation time. * It provides static methods can be used: getInstance to get a system where the region currently applicable implementation class, get back in most areas * is GregorianCalendar, namely: Gregorian implementation class * / public class CalendarDemo1 { public static void main (String [ ] args) { Calendar Calendar = Calendar.getInstance (); System.out.println (Calendar); / * methods * Calendar provided: * date the getTime () * Calendar date of the current may be represented by a return to form date instance. * / A Date DATE = calendar.getTime (); System.out.println (DATE); / * The setTime void * (DATE Date) * Calendar adjusting the current so as to show a given date Date indicated * / calendar.setTime (DATE); } }
/ ** * GET int (int Field) * Get the current value of the specified time Calendar date components corresponding represented. * Component represents a different time, without having to remember a different integers, Calendar provides a number of corresponding constants * / public class CalendarDemo2 { public static void main (String [] args) { Calendar Calendar = Calendar.getInstance (); int = year Calendar.get (Calendar.YEAR); / * * Note from month 0, namely: 0 for January, February 1 represents ... * / int month the Calendar.get = (the Calendar.MONTH) + 1'd ; / * * and "day" time component associated with a: * DAY_OF_MONTH is: month day * DAY_OF_WEEK: days of the week * DAY_OF_YEAR:年中的天 * DATE:月中的天，与DAY_OF_MONTH一致 */ int day = calendar.get(Calendar.DATE); System.out.println(year+"-"+month+"-"+day); int h = calendar.get(Calendar.HOUR_OF_DAY); int m = calendar.get(Calendar.MINUTE); int s = calendar.get(Calendar.SECOND); System.out.println(h+":"+m+":"+s); int days = calendar.get(Calendar.DAY_OF_YEAR); System.out.println("今天是今年的第"+days+"天"); /* * According to the US diet, the first day of the week is Sunday * / Days = Calendar.get (the Calendar.DAY_OF_WEEK) -1 ; String [] Data = { "day", "one", "two", "three" , "four", "five", "six" }; System.out.println ( "today is Week" + Data [Days]); // Get the specified maximum allowed time component int D = calendar.getActualMaximum ( Calendar.DAY_OF_YEAR); System.out.println ( "year, a total" + d + "days" ); } }
/ ** * SET void (Field int, int value) * Calendar specified time adjusted to the given current component value * / public class CalendarDemo3 { public static void main (String [] args) { Calendar Calendar = Calendar.getInstance () ; System.out.println (calendar.getTime ()); // 2008-08-08 20:08:08 // adjustment for the 2008 calendar.set (Calendar.YEAR, 2008 ); // adjust the August calendar .set (the Calendar.MONTH, Calendar.AUGUST); // adjusted number. 8 calendar.set (Calendar.DATE,. 8 ); calendar.set(Calendar.HOUR_OF_DAY, 20); calendar.set(Calendar.MINUTE, 8); calendar.set(Calendar.SECOND, 8); System.out.println(calendar.getTime()); calendar.set(Calendar.DAY_OF_WEEK, Calendar.WEDNESDAY); System.out.println(calendar.getTime()); } }
/ ** * void the Add (Field int, int AMOUNT) * plus a predetermined value to a specified time component, if given a negative value is subtracted. * / Public class CalendarDemo4 { public static void main (String [] args) { Calendar Calendar = Calendar.getInstance (); System.out.println (calendar.getTime ()); / * * See February 3 months and 25 ? after the day of the week Wednesday is the day * / // add three years calendar.add (Calendar.YEAR, 3 ); System.out.println (calendar.getTime ()); // add two months calendar.add (the Calendar.MONTH, 2 ); System.out.println (calendar.getTime ()); //Plus 25 days Calendar.add (Calendar.DAY_OF_YEAR, 25 ); System.out.println (calendar.getTime ()); // adjusted to a week Wednesday calendar.set (the Calendar.DAY_OF_WEEK,. 4 ); the System.out. the println (calendar.getTime ()); } }
/ ** * Calculation merchandising Date * After the program starts, the user to enter the date of production of goods: the MM-dd-YYYY * then enter the number of days the shelf life of the product, is an integer. * Then undergo a process of calculation, the output of the merchandising date, format above. * Rules: * Product expired on Wednesday, two weeks before the date for the promotion. * / Public class Test2 { public static void main (String [] args) throws Exception { Scanner Scanner = new new Scanner (the System.in); System.out.println ( "Please enter the date of production:" ); String STR = Scanner. nextLine (); System.out.println ( "Please enter the number of days of shelf life:" ); int days =The Integer.parseInt (scanner.nextLine ()); the SimpleDateFormat SDF = new new the SimpleDateFormat ( "the MM-dd-YYYY" ); a Date DATE = sdf.parse (STR); // make the production date indicates Calendar Calendar Calendar = Calendar.getInstance ( ); calendar.setTime (dATE); // calculate the expiration date Calendar.add (Calendar.DAY_OF_YEAR, days); // adjust to two weeks before Wednesday Calendar.add (Calendar.DAY_OF_YEAR, -14 ); calendar.set ( the Calendar.DAY_OF_WEEK, . 4 ); DATE = calendar.getTime (); STR= Sdf.format (DATE); System.out.println ( "Promotion date:" + STR); } }