# Java 8 日期时间 API > 原文： [https://javatutorial.net/java-8-date-time-api](https://javatutorial.net/java-8-date-time-api) Java 8 引入了新的日期时间 API，其目的是弥补旧的日期时间 API 的缺点。  以前的日期时间 api 不是线程安全的，新日期时间 api 的替代品是它没有任何设置方法。 新 API 修复的另一个缺点是设计不佳。 旧的 API 具有较少直接的日期操作方法。 而且旧 API 的另一个缺点是程序员必须编写大量代码来处理时区问题。 新的 API 不仅解决了所有这些问题，而且还引入了`java.time`包中的 2 个重要类： * 本地 – 时区处理没有复杂度 * 时区 – 处理各种时区的更复杂的日期时间 API **本地时间 API** 在不需要时区时应使用 **使用主要方法调用**的本地日期时间 API 的示例 ```java import java.time.*; import java.time.format.DateTimeFormatter; public class Main { public static void LocalDateTimeAPI() { LocalDate date = LocalDate.now(); LocalTime time = LocalTime.now(); LocalDateTime now = LocalDateTime.now(); DateTimeFormatter format = DateTimeFormatter.ofPattern("dd-MM-yyyy HH:mm:ss"); String formatedTime = now.format(format); Month month = now.getMonth(); int day = now.getDayOfMonth(); int seconds = now.getSecond(); System.out.println("Current date: " + date); System.out.println("Current time: " + time); System.out.println("Current date and time: " + now); System.out.println("in foramatted manner " + formatedTime); System.out.println("Month: " + month + "\nDay: " + day + "\nSeconds: " + seconds); } public static void main(String[] args) { LocalDateTimeAPI(); } } ``` **输出**： ```java Current date: 2019-07-20 Current time: 14:10:58.492 Current date and time: 2019-07-20T14:10:58.492 in foramatted manner 20-07-2019 14:10:58 Month: JULY Day: 20 Seconds: 58 ``` **时区日期时间 API 示例** ```java import java.time.ZonedDateTime; import java.time.ZoneId; public class ZonedTime { public void testZonedDateTime() { ZoneId zone = ZoneId.of("Europe/Paris"); System.out.println("ZoneId: " + zone); ZoneId currentZone = ZoneId.systemDefault(); System.out.println("CurrentZone: " + currentZone); } public static void main(String args[]) { ZonedTime zonedTimeExample = new ZonedTime(); zonedTimeExample.testZonedDateTime(); } } ``` **输出** ```java ZoneId: Europe/Paris CurrentZone: Europe/London ``` 如您所见，时区日期时间 API 可以让您访问特定时区，还可以为您提供时区或系统的默认时区。 **计时单位示例** ```java import java.time.LocalDate; import java.time.temporal.ChronoUnit; public class ChronoUnits { public void chromoUnits() { LocalDate today = LocalDate.now(); System.out.println("Current date: " + today); LocalDate week = today.plus(1, ChronoUnit.WEEKS); System.out.println("1 week from now: " + week); LocalDate month = today.plus(1, ChronoUnit.MONTHS); System.out.println("1 month from now: " + month); LocalDate year = today.plus(1, ChronoUnit.YEARS); System.out.println("1 year from now: " + year); LocalDate decade = today.plus(1, ChronoUnit.DECADES); System.out.println("1 decade from now: " + decade); } public static void main(String args[]) { ChronoUnits ChronoUnitsExample = new ChronoUnits(); ChronoUnitsExample.chromoUnits(); } } ``` **输出**： ```java Current date: 2019-07-20 1 week from now: 2019-07-27 1 month from now: 2019-08-20 1 year from now: 2020-07-20 1 decade from now: 2029-07-20 ``` **周期和持续时间** 周期处理基于日期的时间，而持续时间处理基于时间的时间。 ```java import java.time.temporal.ChronoUnit; import java.time.LocalDate; import java.time.LocalTime; import java.time.Duration; import java.time.Period; public class PeriodDuration { public void testDuration() { LocalTime currentTime = LocalTime.now(); Duration offtime5 = Duration.ofHours(5); LocalTime timeOff5Hours = currentTime.plus(offtime5); Duration duration = Duration.between(currentTime, timeOff5Hours); System.out.println("Duration: " + duration); } public void testPeriod() { LocalDate currentDate = LocalDate.now(); System.out.println("Current date: " + currentDate); LocalDate nextMonth = currentDate.plus(1, ChronoUnit.MONTHS); System.out.println("Next month: " + nextMonth); Period timePeriod = Period.between(nextMonth, currentDate); System.out.println("Period: " + timePeriod); } public static void main(String args[]) { PeriodDuration periodDuration = new PeriodDuration(); periodDuration.testPeriod(); periodDuration.testDuration(); } } ``` **输出** ```java Current date: 2019-07-20 Next month: 2019-08-20 Period: P-1M Duration: PT-19H ```