java8中新的Date和Time详解

java8中新的Date和Time详解

新Date类和Time类背后的设计原则：

不可变类

java8之前，Date类都是可变类。当我们在多线程环境下使用它，编程人员应该确认Date对象的线程安全。Java8的Date和Time API提供了线程安全的不可变类。编程人员不用考虑并发的问题。

领域模型驱动设计方法

新的日期和时间的类别遵循“域驱动设计”。对于开发者来说，理解方法和类的功能是很容易的。

接下来让我们来看看新Date和Time API:

1.java.time.LocalDate:

LocalDate只提供日期不提供时间信息。它是不可变类且线程安全的。

package org.smarttechie;

import java.time.LocalDate;

import java.time.temporal.ChronoUnit;

/**

* This class demonstrates JAVA 8 data and time API

* @author Siva Prasad Rao Janapati

* */

public class DateTimeDemonstration {

/**

* @param args

*/

public static void main(String[] args) {

//Create date LocalDate localDate = LocalDate.now();

System.out.println("The local date is :: " + localDate);

//Find the length of the month. That is, how many days are there for this month.

System.out.println("The number of days available for this month:: " + localDate.lengthOfMonth());

//Know the month name

System.out.println("What is the month name? :: " + localDate.getMonth().name());

//add 2 days to the today's date.

System.out.println(localDate.plus(2, ChronoUnit.DAYS));

//substract 2 days from today

System.out.println(localDate.minus(2, ChronoUnit.DAYS));

//Convert the string to date

System.out.println(localDate.parse("2017-04-07"));

}

}

2.java.time.LocalTime:

LocalTime只提供时间而不提供日期信息，它是不可变类且线程安全的。

package org.smarttechie;

import java.time.LocalTime;

import java.time.temporal.ChronoUnit;

/**

* This class demonstrates JAVA 8 data and time API

* @author Siva Prasad Rao Janapati

* */

public class DateTimeDemonstration {

/**

* @param args

*/

public static void main(String[] args) {

//Get local time

LocalTime localTime = LocalTime.now();

System.out.println(localTime);

//Get the hour of the day

System.out.println("The hour of the day:: " + localTime.getHour());

//add 2 hours to the time.

System.out.println(localTime.plus(2, ChronoUnit.HOURS));

//add 6 minutes to the time.

System.out.println(localTime.plusMinutes(6));

//substract 2 hours from current time

System.out.println(localTime.minus(2, ChronoUnit.HOURS));

}

}

3.java.time.LocalDateTime:

LocalDateTime提供时间和日期的信息，它是不可变类且线程安全的

package orr.smarttechie;

import java.time.LocalDateTime;

import java.time.temporal.ChronoUnit;

/**

* This class demonstrates JAVA 8 data and time API

* @author Siva Prasad Rao Janapati

*

*/

public class DateTimeDemonstration {

/**

* @param args

*/

public static void main(String[] args) {

//Get LocalDateTime object

LocalDateTime localDateTime = LocalDateTime.now();

System.out.println(localDateTime);

//Find the length of month. That is, how many days are there for this month.

System.out.println("The number of days available for this month:: " + localDateTime.getMonth().length(true));

//Know the month name

System.out.println("What is the month name? :: " + localDateTime.getMonth().name());

//add 2 days to today's date.

System.out.println(localDateTime.plus(2, ChronoUnit.DAYS));

//substract 2 days from today

System.out.println(localDateTime.minus(2, ChronoUnit.DAYS));

}

}

4.java.time.Year:

Year提供年的信息，它是不可变类且线程安全的。

package orr.smarttechie;

import java.time.Year;

import java.time.temporal.ChronoUnit;

/**

* This class demonstrates JAVA 8 data and time API

* @author Siva Prasad Rao Janapati

*

*/

public class DateTimeDemonstration {

/**

* @param args

*/

public static void main(String[] args) {

//Get year

Year year = Year.now();

System.out.println("Year ::" + year);

//know the year is leap year or not

System.out.println("Is year[" +year+"] leap year?"+ year.isLeap());

}

}

5.java.time.Duration:

Duration是用来计算两个给定的日期之间包含多少秒，多少毫秒，它是不可变类且线程安全的

6.java.time.Period:

Period是用来计算两个给定的日期之间包含多少天，多少月或者多少年，它是不可变类且线程安全的

package orr.smarttechie;

import java.time.LocalDate;

import java.time.Period;

import java.time.temporal.ChronoUnit;

/**

* This class demonstrates JAVA 8 data and time API

* @author Siva Prasad Rao Janapati

*

*/

public class DateTimeDemonstration {

/**

* @param args

*/

public static void main(String[] args) {

LocalDate localDate = LocalDate.now();

Period period = Period.between(localDate, localDate.plus(2, ChronoUnit.DAYS));

System.out.println(period.getDays());

}

}

版权声明：本文内容由网络用户投稿，版权归原作者所有，本站不拥有其著作权，亦不承担相应法律责任。如果您发现本站中有涉嫌抄袭或描述失实的内容，请联系我们jiasou666@gmail.com 处理，核实后本网站将在24小时内删除侵权内容。