The Java.time of Java8

Java 8 Java.time Package Tags: Java Java8| Publish time: 2013-10-15 08:29 | CoderbeeShare to:Source: Http://coderbee.net Package Overview

The Java.time package, introduced in JDK8, provides the main APIs for dates, times, instances, and cycles.

The classes defined by the Java.time package represent the rules of the date-time concept, including instants, durations, dates, times, time-zones and periods. These are based on the ISO calendar system, which is followed by Gregorian rules.

All classes are immutable and thread-safe.

Introduction to some classes

• LocalDateTime: Stores the date and time, such as: 2013-10-15T14:43:14.539 .

• Localdate: A date is stored, such as: 2013-10-15 .

• LocalTime: Stores the time, such as: 14:43:14.539 .

The classes above can be combined by the following classes:

• Year: Represents years.

• Month: Represents the months.

• Yearmonth: Indicates the month.

• MonthDay: Indicates the day of the month.

• DayOfWeek: Stores the day of the week.

Examples of conversions between classes:

  LocalDateTime LocalDateTime = Localdatetime.now (); System.out.println ("LocalDateTime:" + localDateTime); Localdate localdate = Localdate.now (); System.out.println ("localdate:" + localdate); LocalTime localtime = Localtime.now (); System.out.println ("localtime:" + localtime);//Gets the current year years = Year.now (); System.out.println ("Year:" + year);//Get Localdatelocaldate localDate1 = Year.atday (59) from year; System.out.println ("localDate1:" + localDate1);//link localtime to a localdate get a localdatetimelocaldatetime localDateTime1 = Localtime.atdate (localDate1); System.out.println ("localDateTime1:" + localDateTime1);//Get a yearyear year1 = Year.of with the specified year (2012); System.out.println ("year1:" + year1);//Get Yearmonthyearmonth Yearmonth = Year1.atmonth from year (2); System.out.println ("Yearmonth:" + yearmonth);//Yearmonth Specify day to get localdatelocaldate LocalDate2 = yearmonth.atday (29); System.out.println ("LocalDate2:" + localDate2);//Judging whether it is a leap year System.out.println ("Isleapyear:" + localdate2.isleapyear () );//February date for automatic processing of leap yearsCreate a Monthdaymonthday MonthDay = Monthday.of (2, 29); Localdate leapyear = monthday.atyear (2012); System.out.println ("leapyear:" + leapyear);//The same monthday is associated to another year localdate nonleapyear = Monthday.atyear (2011); System.out.println ("nonleapyear:" + nonleapyear);

The output of the above code is:

Localdatetime:2013-10-15t15:11:57.489localdate:2013-10-15localtime:15:11:57.489year:2013localdate1 : 2013-02-28localdatetime1:2013-02-28t15:11:57.489year1:2012yearmonth:2012-02localdate2:2012-02-29isleapyear: Trueleapyear:2012-02-29nonleapyear:2011-02-28

Formatting and time calculations

• DateTimeFormatter: Converts between a Date object and a string.

• Chronounit: Calculates the time distance between two points of time, which can be calculated in a variety of time units.

• Temporaladjuster: various date calculation functions.

Continue with the previous code:

  DayOfWeek DayOfWeek = dayofweek.of (1); System.out.println ("DayOfWeek:" + dayOfWeek);//calculates the number of days between two dates, and calculates the interval between two points of time in other time units. Long between = ChronoUnit.DAYS.between (Localdate, leapyear); System.out.println ("Between:" + between);//thread-safe format class, not each time new Simpledateformatdatetimeformatter DateTimeFormatter = Datetimeformatter.ofpattern ("uuuu MM dd");//Convert date time to string identifier System.out.println ("Date Formatter:" + Datetimeformatter.format (Nonleapyear));//parse the date time as a string temporalaccessor temporalaccessor = Datetimeformatter.parse ( "2013 01 15"); System.out.println ("Temporalaccessor:" + localdate.from (temporalaccessor)); Instant Instant = Instant.now (); Timestamp System.out.println ("Instant:" + instant);//Calculate the date of the first day of the month localdate with = Nonleapyear.with ( Temporaladjuster.firstdayofmonth ()); System.out.println ("with:" + with);//Calculates the date of the first Monday of a month temporaladjuster Temporaladjuster = Temporaladjuster.firstinmonth (Dayofweek.monday); Localdate with1 = Localdate.with (Temporaladjuster); System.out.println ("with1:" + with1);//Calculation LOcaldate the next Monday's date localdate with2 = Localdate.with (Temporaladjuster.next (dayofweek.monday)); System.out.println ("with2:" + with2);

Output:

Dayofweek:mondaybetween: -594date formatter:2011 28temporalaccessor:2013-01-15instant:2013-10-15t07 : 55:30.964zwith:2011-02-01with1:2013-10-07with2:2013-10-21

Java.util.Date conversion to a new library class

Conversions can be done in the following ways.

  Date.toInstant()Date.from(Instant)Calendar.toInstant()

Method overview

The package's API provides a number of related methods, which generally have a consistent method prefix:

• Of: Static Factory method.
• Parse: Static Factory method, focusing on parsing.
• Get: Gets the value of something.
• is: Check if something is true.
• With: Immutable setter equivalents.
• Plus: Add some amount to an object.
• Minus: Subtracts some amount from an object.
• To: Convert to another type.
• At: Combine this object with another object, for example: date.atTime(time) .

Recall that the previous statements are processed in the stored procedure date, because Java's date operation is indeed too weak. With Java 8, mom doesn't have to worry about me working on the date any more.

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Java8 java.time